The social causes of the Russian Revolution can be derived from centuries of oppression of the lower classes by the Tsarist regime and Nicholas's failures in World War I. While rural agrarian peasants had been emancipated from serfdom in 1861, they still resented paying redemption payments to the state, and demanded communal tender of the land they worked. The problem was further compounded by the failure of Sergei Witte's land reforms of the early 20th century. Increasing peasant disturbances and sometimes actual revolts occurred, with the goal of securing ownership of the land they worked. Russia consisted mainly of poor farming peasants and substantial inequality of land ownership, with 1.5% of the population owning 25% of the land.

The rapid industrialization of Russia also resulted in urban overcrowding and poor conditions for urban industrial workers (as mentioned above). Between 1890 and 1910, the population of the capital, Saint Petersburg, swelled from 1,033,600 to 1,905,600, with Moscow experiencing similar growth. This created a new 'proletariat' which, due to being crowded together in the cities, was much more likely to protest and go on strike than the peasantry had been in previous times. In one 1904 survey, it was found that an average of 16 people shared each apartment in Saint Petersburg, with six people per room. There was also no running water, and piles of human waste were a threat to the health of the workers. The poor conditions only aggravated the situation, with the number of strikes and incidents of public disorder rapidly increasing in the years shortly before World War I. Because of late industrialization, Russia's workers were highly concentrated. By 1914, 40% of Russian workers were employed in factories of 1,000+ workers (32% in 1901). 42% worked in 100–1,000 worker enterprises, 18% in 1–100 worker businesses (in the US, 1914, the figures were 18, 47 and 35 respectively).

Many sections of the country had reason to be dissatisfied with the existing autocracy. Nicholas II was a deeply conservative ruler and maintained a strict authoritarian system. Individuals and society in general were expected to show self-restraint, devotion to community, deference to the social hierarchy and a sense of duty to the country. Religious faith helped bind all of these tenets together as a source of comfort and reassurance in the face of difficult conditions and as a means of political authority exercised through the clergy. Perhaps more than any other modern monarch, Nicholas II attached his fate and the future of his dynasty to the notion of the ruler as a saintly and infallible father to his people.

Despite constant oppression, the desire of the people for democratic participation in government decisions was strong. Since the Age of Enlightenment, Russian intellectuals had promoted Enlightenment ideals such as the dignity of the individual and the rectitude of democratic representation. These ideals were championed most vociferously by Russia's liberals, although populists, Marxists, and anarchists also claimed to support democratic reforms. A growing opposition movement had begun to challenge the Romanov monarchy openly well before the turmoil of World War I.

In late 1893, Vladimir Ilyich Ulyanov, better known as Vladimir Lenin, moved to Saint Petersburg. There, he worked as a barrister's assistant and rose to a senior position in a Marxist revolutionary cell that called itself the Social-Democrats after the Marxist Social Democratic Party of Germany. Publicly championing Marxism within the socialist movement, he encouraged the founding of revolutionary cells in Russia's industrial centres. By late 1894, he was leading a Marxist workers' circle, and meticulously covered his tracks, knowing that police spies tried to infiltrate the movement.

Lenin hoped to cement connections between his Social-Democrats and Emancipation of Labour, a group of Russian Marxist émigrés based in Switzerland; he visited the country to meet group members Plekhanov and Pavel Axelrod. He proceeded to Paris to meet Marx's son-in-law Paul Lafargue and to research the Paris Commune of 1871, which he considered an early prototype for a proletarian government. Returning to Russia with a stash of illegal revolutionary publications, he travelled to various cities distributing literature to striking workers. While involved in producing a news sheet, Rabochee delo (Workers' Cause), he was among 40 activists arrested in St. Petersburg and charged with sedition.

In February 1897, Lenin was sentenced without trial to three years' exile in eastern Siberia. Deemed only a minor threat to the government, he was exiled to a peasant's hut in Shushenskoye, Minusinsky District, where he was kept under police surveillance; he was nevertheless able to correspond with other revolutionaries, many of whom visited him, and permitted to go on trips to swim in the Yenisei River and to hunt duck and snipe. After his exile, Lenin settled in Pskov in early 1900. There, he began raising funds for a newspaper, Iskra (Spark), a new organ of the Russian Marxist party, now calling itself the Russian Social Democratic Labour Party (RSDLP). In July 1900, Lenin left Russia for Western Europe; in Switzerland he met other Russian Marxists, and at a Corsier conference they agreed to launch the paper from Munich, where Lenin relocated in September. Containing contributions from prominent European Marxists, Iskra was smuggled into Russia, becoming the country's most successful underground publication for 50 years.

Seeing Russia Empire as a rival, Japan offered to recognize Russian dominance in Manchuria in exchange for recognition of the Korean Empire as being within the Japanese sphere of influence. Russia refused and demanded the establishment of a neutral buffer zone between Russia and Japan in Korea, north of the 39th parallel. The Imperial Japanese Government perceived this as obstructing their plans for expansion into mainland Asia and chose to go to war. After negotiations broke down in 1904, the Imperial Japanese Navy opened hostilities in a surprise attack on the Russian Eastern Fleet at Port Arthur, China on 9 February 1904.

Although Russia suffered a number of defeats, Emperor Nicholas II remained convinced that Russia could still win if it fought on; he chose to remain engaged in the war and await the outcomes of key naval battles. As hope of victory dissipated, he continued the war to preserve the dignity of Russia by averting a "humiliating peace." Russia ignored Japan's willingness early on to agree to an armistice and rejected the idea of bringing the dispute to the Permanent Court of Arbitration at the Hague. The war was eventually concluded with the Treaty of Portsmouth (5 September 1905), mediated by US President Theodore Roosevelt. The complete victory of the Japanese military surprised international observers and transformed the balance of power in both East Asia and Europe, resulting in Japan's emergence as a great power and a decline in the Russian Empire's prestige and influence in Europe. Russia's incurrence of substantial casualties and losses for a cause that resulted in humiliating defeat contributed to a growing domestic unrest which culminated in the 1905 Russian Revolution, and severely damaged the prestige of the Russian autocracy.

Bloody Sunday was the series of events on Sunday, 22 January 1905 in St Petersburg, Russia, when unarmed demonstrators, led by Father Georgy Gapon, were fired upon by soldiers of the Imperial Guard as they marched towards the Winter Palace to present a petition to Tsar Nicholas II of Russia. Bloody Sunday caused grave consequences for the Tsarist autocracy governing Imperial Russia: the events in St. Petersburg provoked public outrage and a series of massive strikes that spread quickly to the industrial centres of the Russian Empire. The massacre on Bloody Sunday is considered to be the start of the active phase of the Revolution of 1905.

The Russian Revolution of 1905, also known as the First Russian Revolution, occurred on 22 January 1905, and was a wave of mass political and social unrest that spread through vast areas of the Russian Empire. The mass unrest was directed against the Tsar, nobility, and ruling class. It included worker strikes, peasant unrest, and military mutinies.

The 1905 revolution was primarily spurred by the international humiliation as a result of the Russian defeat in the Russo-Japanese War, which ended in the same year. Calls for revolution were intensified by the growing realisation by a variety of sectors of society of the need for reform. Politicians such as Sergei Witte had succeeded in partially industrializing Russia but failed to reform and modernize Russia socially.

Calls for radicalism were present in the 1905 Revolution, but many of the revolutionaries who were in a position to lead were either in exile or in prison while it took place. The events in 1905 demonstrated the precarious position in which the Tsar found himself. As a result, Tsarist Russia did not undergo sufficient reform, which had a direct impact on the radical politics brewing in the Russian Empire. Although the radicals were still in the minority of the populace, their momentum was growing. Vladimir Lenin, a revolutionary himself, would later say that the Revolution of 1905 was "The Great Dress Rehearsal", without which the "victory of the October Revolution in 1917 would have been impossible".

In response to the public pressure, Tsar Nicholas II enacted some constitutional reform (namely the October Manifesto). The October Manifesto is a document that served as a precursor to the Russian Empire's first Constitution, which was adopted the following year in 1906. The Manifesto was issued by Tsar Nicholas II, under the influence of Sergei Witte, on 30 October 1905 as a response to the Russian Revolution of 1905. Nicholas strenuously resisted these ideas, but gave in after his first choice to head a military dictatorship, Grand Duke Nicholas, threatened to shoot himself in the head if the Tsar did not accept Witte's suggestion. Nicholas reluctantly agreed, and issued what became known as the October Manifesto, promising basic civil rights and an elected parliament called the Duma, without whose approval no laws were to be enacted in Russia in the future. According to his memoirs, Witte did not force the Tsar to sign the October Manifesto, which was proclaimed in all the churches.

Despite popular participation in the Duma, the parliament was unable to issue laws of its own, and frequently came into conflict with Nicholas. Its power was limited and Nicholas continued to hold the ruling authority. Furthermore, he could dissolve the Duma, which he often did.

Rasputin first met the tsar on 1 November 1905, at the Peterhof Palace. The tsar recorded the event in his diary, writing that he and Alexandra had "made the acquaintance of a man of God – Grigory, from Tobolsk province". Rasputin returned to Pokrovskoye shortly after their first meeting and did not return to St. Petersburg until July 1906. On his return, Rasputin sent Nicholas a telegram asking to present the tsar with an icon of Simeon of Verkhoturye. He met with Nicholas and Alexandra on 18 July and again in October, when he first met their children. At some point, the royal family became convinced that Rasputin possessed the miraculous power to heal Alexei, but historians disagree over when: according to Orlando Figes, Rasputin was first introduced to the tsar and tsarina as a healer who could help their son in November 1905, while Joseph Fuhrmann has speculated that it was in October 1906 that Rasputin was first asked to pray for the health of Alexei.

The Imperial Family's belief in Rasputin's healing powers brought him considerable status and power at court. Rasputin used his position to full effect, accepting bribes and sexual favors from admirers and working diligently to expand his influence. Rasputin soon became a controversial figure; he was accused by his enemies of religious heresy and rape, was suspected of exerting undue political influence over the tsar, and was even rumored to be having an affair with the tsarina.

The outbreak of World War I in August 1914 initially served to quiet the prevalent social and political protests, focusing hostilities against a common external enemy, but this patriotic unity did not last long. As the war dragged on inconclusively, war-weariness gradually took its toll. Russia's first major battle of the war was a disaster; in the 1914 Battle of Tannenberg, over 30,000 Russian troops were killed or wounded and 90,000 captured, while Germany suffered just 12,000 casualties. In the autumn of 1915, Nicholas had taken direct command of the army, personally overseeing Russia's main theatre of war and leaving his ambitious but incapable wife Alexandra in charge of the government. Reports of corruption and incompetence in the Imperial government began to emerge, and the growing influence of Grigori Rasputin in the Imperial family was widely resented.

In 1915, things took a critical turn for the worse when Germany shifted its focus of attack to the Eastern Front. The superior German Army – better led, better trained, and better supplied – was quite effective against the ill-equipped Russian forces, driving the Russians out of Galicia, as well as Russian Poland during the Gorlice–Tarnów Offensive campaign. By the end of October 1916, Russia had lost between 1,600,000 and 1,800,000 soldiers, with an additional 2,000,000 prisoners of war and 1,000,000 missing, all making up a total of nearly 5,000,000 men. These staggering losses played a definite role in the mutinies and revolts that began to occur. In 1916, reports of fraternizing with the enemy began to circulate. Soldiers went hungry, lacked shoes, munitions, and even weapons. Rampant discontent lowered morale, which was further undermined by a series of military defeats. The army quickly ran short of rifles and ammunition (as well as uniforms and food), and by mid-1915, men were being sent to the front bearing no arms. It was hoped that they could equip themselves with arms recovered from fallen soldiers, of both sides, on the battlefields. The soldiers did not feel as if they were valuable, rather they felt as if they were expendable.

The war did not only devastate soldiers. By the end of 1915, there were manifold signs that the economy was breaking down under the heightened strain of wartime demand. The main problems were food shortages and rising prices. Inflation dragged incomes down at an alarmingly rapid rate, and shortages made it difficult for an individual to sustain oneself. Conditions became increasingly difficult to afford food and physically obtain it.

Tsar Nicholas was blamed for all of these crises, and what little support he had left began to crumble. As discontent grew, the State Duma issued a warning to Nicholas in November 1916, stating that, inevitably, a terrible disaster would grip the country unless a constitutional form of government was put in place.

World War I, the dissolution of feudalism, and a meddling government bureaucracy all contributed to Russia's rapid economic decline. Many laid the blame on Alexandria and Rasputin. One outspoken member of the Duma, far-right politician Vladimir Purishkevich, stated in November 1916 that the tsar's ministers had "been turned into marionettes, marionettes whose threads have been taken firmly in hand by Rasputin and the Empress Alexandra Fyodorovna – the evil genius of Russia and the Tsarina… who has remained a German on the Russian throne and alien to the country and its people".

A group of nobles led by Prince Felix Yusupov, Grand Duke Dmitri Pavlovich, and right-wing politician Vladimir Purishkevich decided that Rasputin's influence over the tsarina threatened the empire, and they concocted a plan in to kill him. On December 30, 1916, Rasputin was murdered during the early morning at the home of Felix Yusupov. He died of three gunshot wounds, one of which was a close-range shot to his forehead. Little is certain about his death beyond this, and the circumstances of his death have been the subject of considerable speculation. According to historian Douglas Smith, "what really happened at the Yusupov home on 17 December will never be known".

On March 8, 1917, in Petrograd, women textile workers began a demonstration that eventually engulfed the whole city, demanding "Bread and Peace"—an end to World War I, to food shortages, and to czarism. This marked the beginning of the February Revolution, which alongside the October Revolution, made up the second Russian Revolution. Revolutionary leader Leon Trotsky wrote, "8th March was International Woman's Day and meetings and actions were foreseen. But we did not imagine that this 'Women's Day' would inaugurate the revolution. Revolutionary actions were foreseen but without a date. But in the morning, despite the orders to the contrary, textile workers left their work in several factories and sent delegates to ask for the support of the strike… which led to mass strike... all went out into the streets." Seven days later, Tsar Nicholas II abdicated, and the provisional Government granted women the right to vote.

The main events of the February Revolution took place in and near Petrograd (present-day Saint Petersburg), where long-standing discontent with the monarchy erupted into mass protests against food rationing on March 8. Three days later Tsar Nicholas II abdicated, ending Romanov dynastic rule and the Russian Empire. The Russian Provisional Government under Prince Georgy Lvov replaced the Council of Ministers of Russia. Revolutionary activity lasted about eight days, involving mass demonstrations and violent armed clashes with police and gendarmes, the last loyal forces of the Russian monarchy. In all, over 1,300 people were killed during the protests of February 1917.

The Provisional Government proved deeply unpopular and was forced to share dual power with the Petrograd Soviet. After the July Days, in which the Government killed hundreds of protesters, Alexander Kerensky became head of Government. He was unable to fix Russia's immediate problems, including food shortages and mass unemployment, as he attempted to keep Russia involved in the ever more unpopular war.

After Tsar Nicholas II abdicated, the State Duma took over control of the country, establishing the Russian Provisional Government and converting the Empire into a new Russian Republic. When Lenin learned of this from his base in Switzerland, he celebrated with other dissidents. He decided to return to Russia to take charge of the Bolsheviks but found that most passages into the country were blocked due to the ongoing conflict. He organised a plan with other dissidents to negotiate a passage for them through Germany, with whom Russia was then at war. Recognising that these dissidents could cause problems for their Russian enemies, the German government agreed to permit 32 Russian citizens to travel by train through their territory, among them Lenin and his wife. For political reasons, Lenin and the Germans agreed to adhere to a cover story that Lenin had travelled by sealed train carriage through German territory, but in fact the journey was not truly by sealed train because the passengers were allowed to disembark to, for example, spend the night in Frankfurt The group travelled by train from Zürich to Sassnitz, proceeding by ferry to Trelleborg, Sweden, and from there to the Haparanda–Tornio border crossing and then to Helsinki before taking the final train to Petrograd in disguise.

Arriving at Petrograd's Finland Station in April, Lenin gave a speech to Bolshevik supporters condemning the Provisional Government and again calling for a continent-wide European proletarian revolution. Over the following days, he spoke at Bolshevik meetings, lambasting those who wanted reconciliation with the Mensheviks and revealing his "April Theses", an outline of his plans for the Bolsheviks, which he had written on the journey from Switzerland.

The July Days were a period of unrest in Petrograd, Russia, between 16–20 July 1917. It was characterised by spontaneous armed demonstrations by soldiers, sailors, and industrial workers engaged against the Russian Provisional Government. The demonstrations were angrier and more violent than those during the February Revolution months earlier. The Provisional Government blamed the Bolsheviks for the violence brought about by the July Days and in a subsequent crackdown on the Bolshevik Party, the party was dispersed, many of the leadership arrested. Vladimir Lenin fled to Finland, while Leon Trotsky was among those arrested. The outcome of the July Days represented a temporary decline in the growth of Bolshevik power and influence in the period before the October Revolution.

The Kornilov affair, or the Kornilov putsch, was an attempted military coup d'état by the commander-in-chief of the Russian Army, General Lavr Kornilov, from 27–30 August 1917, against the Russian Provisional Government headed by Aleksander Kerensky and the Petrograd Soviet of Soldiers' and Workers' Deputies. The biggest beneficiary of the Kornilov affair was the Bolshevik Party, who enjoyed a revival in support and strength in the wake of the attempted coup. Kerensky released Bolsheviks who had been arrested during the July Days a few months earlier, when Vladimir Lenin was accused of being in the pay of the Germans and subsequently fled to Finland. Kerensky's plea to the Petrograd Soviet for support had resulted in the rearmament of the Bolshevik Military Organization and the release of Bolshevik political prisoners, including Leon Trotsky. Though these weapons were not needed to fight off Kornilov's advancing troops in August, they were kept by the Bolsheviks and used in their own successful armed October Revolution. Bolshevik support amongst the Russian public also increased following the Kornilov affair, a consequence of dissatisfaction with the Provisional Government's handling of Kornilov's attempted seizure of power. Following the October Revolution, Lenin and the Bolsheviks seized power and the Provisional Government that Kornilov was a part of ceased to exist. The fragments of the Provisional Government were a pivotal force in the Russian Civil War that occurred in response to Lenin's seizure of power.

In Finland, Lenin had worked on his book State and Revolution and continued to lead his party, writing newspaper articles and policy decrees. By October, he returned to Petrograd (present-day St. Petersburg), aware that the increasingly radical city presented him no legal danger and a second opportunity for revolution. Recognizing the strength of the Bolsheviks, Lenin began pressing for the immediate overthrow of the Kerensky government by the Bolsheviks. Lenin was of the opinion that taking power should occur in both St. Petersburg and Moscow simultaneously, parenthetically stating that it made no difference which city rose up first, but expressing his opinion that Moscow may well rise up first. The Bolshevik Central Committee drafted a resolution, calling for the dissolution of the Provisional Government in favor of the Petrograd Soviet. The resolution was passed 10–2 (Lev Kamenev and Grigory Zinoviev prominently dissenting) promoting the October Revolution.

On 23 October 1917, the Petrograd Soviet, led by Trotsky, voted to back a military uprising. On 6 November, the government shut down numerous newspapers and closed the city of Petrograd in an attempt to forestall the revolution; minor armed skirmishes broke out. The next day a full scale uprising erupted as a fleet of Bolshevik sailors entered the harbor and tens of thousands of soldiers rose up in support of the Bolsheviks. Bolshevik Red Guards forces under the Military-Revolutionary Committee began the occupation of government buildings on 7 November, 1917. A final assault against the Winter Palace—against 3,000 cadets, officers, cossacks, and female soldiers—was not vigorously resisted. The Bolsheviks delayed the assault because they could not find functioning artillery At 6:15 p.m., a large group of artillery cadets abandoned the palace, taking their artillery with them. At 8:00 p.m., 200 cossacks left the palace and returned to their barracks.

While the cabinet of the provisional government within the palace debated what action to take, the Bolsheviks issued an ultimatum to surrender. Workers and soldiers occupied the last of the telegraph stations, cutting off the cabinet's communications with loyal military forces outside the city. As the night progressed, crowds of insurgents surrounded the palace, and many infiltrated it. At 9:45 p.m, the cruiser Aurora fired a blank shot from the harbor. Some of the revolutionaries entered the palace at 10:25 p.m. and there was a mass entry 3 hours later. By 2:10 a.m. on 26 October, Bolshevik forces had gained control. The Cadets and the 140 volunteers of the Women's Battalion surrendered rather than resist the 40,000 strong attacking force. After sporadic gunfire throughout the building, the cabinet of the Provisional Government surrendered, and were imprisoned in Peter and Paul Fortress. The only member who was not arrested was Kerensky himself, who had already left the palace. With the Petrograd Soviet now in control of government, garrison, and proletariat, the Second All Russian Congress of Soviets held its opening session on the day, while Trotsky dismissed the opposing Mensheviks and the Socialist Revolutionaries (SR) from Congress.

The Russian Civil War, which broke out in 1918 shortly after the October Revolution, resulted in the deaths and suffering of millions of people regardless of their political orientation. The war was fought mainly between the Red Army ("Reds"), consisting of the uprising majority led by the Bolshevik minority, and the "Whites" – army officers and cossacks, the "bourgeoisie", and political groups ranging from the far Right, to the Socialist Revolutionaries who opposed the drastic restructuring championed by the Bolsheviks following the collapse of the Provisional Government, to the Soviets (under clear Bolshevik dominance). The Whites had backing from other countries such as the United Kingdom, France, the United States, and Japan, while the Reds possessed internal support, proving to be much more effective. Though the Allied nations, using external interference, provided substantial military aid to the loosely knit anti-Bolshevik forces, they were ultimately defeated.

The Bolsheviks firstly assumed power in Petrograd, expanding their rule outwards. They eventually reached the Easterly Siberian Russian coast in Vladivostok, four years after the war began, an occupation that is believed to have ended all significant military campaigns in the nation. Less than one year later, the last area controlled by the White Army, the Ayano-Maysky District, directly to the north of the Krai containing Vladivostok, was given up when General Anatoly Pepelyayev capitulated in 1923.

Elections to the Russian Constituent Assembly were held on 25 November 1917, although some districts had polling on alternate days, around two months after they were originally meant to occur, having been organized as a result of events in the February Revolution. They are generally recognised to be the first free elections in Russian history.

Various academic studies have given alternative results. However, all clearly indicate that the Bolsheviks were clear winners in the urban centres, and also took around two-thirds of the votes of soldiers on the Western Front. Nevertheless, the Socialist-Revolutionary party topped the polls, winning a plurality of seats (no party won a majority) on the strength of support from the country's rural peasantry, who were for the most part one-issue voters, that issue being land reform.

The elections, however, did not produce a democratically-elected government. The Constituent Assembly only met for a single day the following January before being dissolved by the Bolsheviks. All opposition parties were ultimately banned, and the Bolsheviks ruled the country as a one-party state.

The Treaty of Brest-Litovsk was a separate peace treaty signed on 3 March 1918 between Russia and the Central Powers (Germany, Austria-Hungary, Bulgaria, and the Ottoman Empire), that ended Russia's participation in World War I. The treaty was agreed upon by the Russians to stop further invasion. As a result of the treaty, Soviet Russia defaulted on all of Imperial Russia's commitments to the Allies and eleven nations became independent in eastern Europe and western Asia. Under the treaty, Russia lost all of Ukraine and most of Belarus, as well as its three Baltic republics of Lithuania, Latvia, and Estonia (so-called Baltic governorates in the Russian Empire), and these three regions became German vassal states under German princelings. Russia also ceded its province of Kars in the South Caucasus to the Ottoman Empire. The treaty was annulled by the Armistice of 11 November 1918, when Germany surrendered to the western Allied Powers. However, in the meantime it did provide some relief to the Bolsheviks, already fighting the Russian Civil War (1917–1922) following the Russian Revolutions of 1917, by the renunciation of Russia's claims on Poland, Belarus, Ukraine, Finland, Estonia, Latvia, and Lithuania.

Following the February Revolution in 1917, the Romanov family and their servants had been imprisoned in the Alexander Palace before being moved to Tobolsk, Siberia in the aftermath of the October Revolution. They were next moved to a house in Yekaterinburg, near the Ural Mountains. On the night of 16–17 July 1918, the Russian Imperial Romanov family were shot and bayoneted to death by Bolshevik revolutionaries under Yakov Yurovsky on the orders of the Ural Regional Soviet in Yekaterinburg. Most historians attribute the execution order to the government in Moscow, specifically Vladimir Lenin and Yakov Sverdlov, who wanted to prevent the rescue of the Imperial family by the approaching Czechoslovak Legion during the ongoing Russian Civil War. This is supported by a passage in Leon Trotsky's diary. A 2011 investigation concluded that, despite the opening of state archives in the post-Soviet years, no written document has been found which proves Lenin or Sverdlov ordered the executions; however, they endorsed the murders after they occurred. Other sources argue that Lenin and the central Soviet government had wanted to conduct a trial of the Romanovs, with Trotsky serving as prosecutor, but that the local Ural Soviet, under pressure from Left Socialist-Revolutionaries and anarchists, undertook the executions on their own initiative due to the approach of the Czechoslovaks.

The Red Terror was a campaign of political repression and executions carried out by the Bolsheviks, chiefly through the Cheka, the Bolshevik secret police. It started in late August 1918 after the beginning of the Russian Civil War and lasted until 1922. Arising after assassination attempts on Vladimir Lenin and Petrograd Cheka leader Moisei Uritsky, the latter of which was successful, the Red Terror was modeled on the Reign of Terror of the French Revolution, and sought to eliminate political dissent, opposition, and any other threat to Bolshevik power. More broadly, the term is usually applied to Bolshevik political repression throughout the Civil War (1917–1922), as distinguished from the White Terror carried out by the White Army (Russian and non-Russian groups opposed to Bolshevik rule) against their political enemies, including the Bolsheviks.

Estimates for the total number of victims of Bolshevik repression vary widely in numbers and scope. One source gives estimates of 28,000 executions per year from December 1917 to February 1922. Estimates for the number of people shot during the initial period of the Red Terror are at least 10,000. Estimates for the whole period go for a low of 50,000 to highs of 140,000 and 200,000 executed. The most reliable estimations for the number of executions in total put the number at about 100,000.

The Communist International (Comintern), also known as the Third International, was a Soviet-controlled international organization founded in 1919 that advocated world communism. The Comintern resolved at its Second Congress to "struggle by all available means, including armed force, for the overthrow of the international bourgeoisie and the creation of an international Soviet republic as a transition stage to the complete abolition of the state". The Comintern was preceded by the 1916 dissolution of the Second International. The Comintern held seven World Congresses in Moscow between 1919 and 1935. During that period, it also conducted thirteen Enlarged Plenums of its governing Executive Committee, which had much the same function as the somewhat larger and more grandiose Congresses. Joseph Stalin, leader of the Soviet Union, dissolved the Comintern in 1943 to avoid antagonizing his allies in the later years of World War II, the United States and the United Kingdom. It was succeeded by the Cominform in 1947.

In 1921, as the Civil War was drawing to a close, Lenin proposed the New Economic Policy (NEP), a system of state capitalism that started the process of industrialization and post-war recovery. The NEP ended a brief period of intense rationing called "war communism" and began a period of a market economy under Communist dictation. The Bolsheviks believed at this time that Russia, being among the most economically undeveloped and socially backward countries in Europe, had not yet reached the necessary conditions of development for socialism to become a practical pursuit and that this would have to wait for such conditions to arrive under capitalist development as had been achieved in more advanced countries such as England and Germany. 

The NEP represented a more market-oriented economic policy (deemed necessary after the Russian Civil War of 1918 to 1922) to foster the economy of the country, which had suffered severely since 1915. The Soviet authorities partially revoked the complete nationalization of industry (established during the period of war communism of 1918 to 1921) and introduced a mixed economy which allowed private individuals to own small and medium sized enterprises, while the state continued to control large industries, banks and foreign trade.

The Russian famine of 1921–1922 was a severe famine in the Russian Soviet Federative Socialist Republic which began early in the spring of 1921 and lasted through 1922. The famine resulted from the combined effects of economic disturbance because of the Russian Revolution and Russian Civil War, the government policy of war communism (especially prodrazvyorstka), exacerbated by rail systems that could not distribute food efficiently. This famine killed an estimated 5 million people, primarily affecting the Volga and Ural River regions, and peasants resorted to cannibalism. Hunger was so severe that it was likely seed-grain would be eaten rather than sown. At one point, relief agencies had to give food to railroad staff to get their supplies moved.

On 30 December 1922, the Russian SFSR joined former territories of the Russian Empire to form the Union of Soviet Socialist Republics (USSR), of which Lenin was elected leader. On 9 March 1923, Lenin suffered a stroke, which incapacitated him and effectively ended his role in government. He died on 21 January 1924, only thirteen months after the founding of the Soviet Union, of which he would become regarded as the founding father.