COMPLETE interruption of the aortic arch has been reviewed recently.1Most cases had an associated patent ductus arteriosus (98%) or ventricular septal defects (93%), or both. A small percent had more complex malformations. In four instances (3.8%), origin of both great vessels from the right ventricle was found. We are reporting such a case in which the diastolic pressure was significantly lower in the leg than in the arm. This finding might suggest the diagnosis of interrupted aortic arch. Report of a Case The patient, a 4,445 gm (19 lb 12½ ounce) Negro male infant was delivered spontaneously to a gravida 4, para 3 diabetic mother after a term pregnancy. He had an Apgar score of 9 and normal physical findings. At age 3 days, he developed jaundice (lasting five days). On the next day, tachycardia, tachypnea, and poor feeding were noted. A chest x-ray film showed slight cardiomegaly,