After the Battle of Lake Trasimene, the prisoners were badly treated if they were Romans; the Latin allies who were captured were well treated by the Carthaginians and many were freed and sent back to their cities, in the hope they would speak well of Carthaginian martial prowess and of their treatment. Hannibal hoped some of these allies could be persuaded to defect. The Carthaginians continued their march through Etruria, then Umbria, to the Adriatic coast, then turned south into Apulia, in the hope of winning over some of the ethnic Greek and Italic city states of southern Italy.

News of the defeat again caused a panic in Rome. Quintus Fabius Maximus was elected dictator by the Roman Assembly and adopted the "Fabian strategy" of avoiding pitched battles, relying instead on low-level harassment to wear the invader down, until Rome could rebuild its military strength. Hannibal was left largely free to ravage Apulia for the next year. Fabius was not popular among the soldiers, the Roman public or the Roman elite, since he avoided battle while Italy was being devastated by the enemy and his tactics would not lead to a quick end to the war.Hannibal marched through the richest and most fertile provinces of Italy, hoping the devastation would draw Fabius into battle, but Fabius refused.

The Roman populace derided Fabius as the Cunctator ("the Delayer") and at the elections of 216 BCE elected new consuls: Gaius Terentius Varro, who advocated pursuing a more aggressive war strategy, and Lucius Aemilius Paullus, who advocated a strategy somewhere between Fabius's and that suggested by Varro. In the spring of 216 BCE Hannibal seized the large supply depot at Cannae on the Apulian plain. The Roman Senate authorized the raising of double-sized armies by Varro and Paullus, a force of 86,000 men, the largest in Roman history up to that point.