We report a 61 years old male presenting with a right cerebral infarction, along with a type I persistent left proatlantal artery (PA), which is a form of primitive carotid-basilar anastomosis. The patient had an absence of the ipsilateral vertebral artery (VA) and hypoplasia of the contralateral VA, while the basilar artery was supplied by the PA. Other vascular anomalies present were a fusiform aneurysm of the right subclavian artery, and an A1 segment aplasia of the hypoplastic anterior right cerebral artery, which originated from the anterior communicating artery. To our knowledge these anomalies were not described previously.