Upon the Conquest of Mecca in January 630, Utbah and his brother Muattib withdrew to the edge of Mecca with the other polytheists. Muhammad asked his uncle al-Abbas to bring them to him. They were brought, and at Muhammad's invitation, they converted to Islam and took the oath of allegiance. Al-Abbas remarked that Muhammad's face was "reflecting joy" at their conversion. Utbah joined the Islamic army and fought at Hunayn. He was among those who did not abandon Muhammad in the battle.