Dysmorphic facial features were present in 9 of 31 children with tetralogy of Fallot anatomy (29%). These anomalies included hypertelorism, low-set ears, small mouth, short philtrum, and micrognathia. Ten children had pulmonary atresia, 13 (42%) had a right aortic arch, and 13 had extracardiac congenital anomalies. There were 16 children in the series (52%) who had hospital admissions for important or recurrent infections, and 18 who had immune deficiency: low levels of T lymphocytes were found in 9, low levels of complement in 8, and low immunoglobulins in 3. Embryologically, the cardiac outflow tracts, the aortic arch, the face, and the thymus develop at the same time, and all receive migrating cells from the neural crest. Teratogenic factors possibly produce this constellation of anomalies, which is in the spectrum of the Di George syndrome (third and fourth pharyngeal pouch syndrome). It is of importance for the management of such children, that their immune deficiency be recognized and treated appropriately.