We report the 1st known case in which truncus arteriosus and double aortic arch have been associated with DiGeorge syndrome. The association of these 2 cardiovascular anomalies lends support, by itself, to speculation that truncus arteriosus and double aortic arch have a common embryonic pathogenesis; and the presence of these anomalies in a patient with DiGeorge syndrome strengthens the contention that the common causative factor is pathologic development of the neural crest cells.