We discuss the arterial supply of the cranial nerves from their exit out of the brain stem to their exit from the skull base. Four distinct groups can be differentiated from an embryologic and phylogenetic standpoint. Understanding the arterial supply to the cranial nerves and the potential anastomoses is paramount in the endovascular treatment of dural AV shunts and highly vascularized tumors of the skull base to avoid neurologic deficits.