Al-Bursuqi besieged the town of Azaz, to the north of Aleppo, in territory belonging to the County of Edessa. Baldwin II, Leo I of Armenia, Joscelin I, and Pons of Tripoli, with a force of 1,100 knights from their respective territories (including knights from Antioch, where Baldwin was regent), as well as 2,000 infantry, met al-Bursuqi outside Azaz, where the Seljuk atabeg had gathered his much larger force. Baldwin pretended to retreat, thereby drawing the Seljuks away from Azaz into the open where they were surrounded. After a long and bloody battle, the Seljuks were defeated and their camp captured by Baldwin, who took enough loot to ransom the prisoners taken by the Seljuks (including the future Joscelin II of Edessa).

The number of Muslim troops killed was more than 1,000, according to Ibn al-Athir. William of Tyre gave 24 dead for the Crusaders and 2,000 for the Muslims. Apart from relieving Azaz, this victory allowed the Crusaders to regain much of the influence they had lost after their defeat at Ager Sanguinis in 1119.