The object of this paper is to report two infants with hypoplasia of the left side of the heart and ascending aorta, premature obliteration of the foramen ovale, and a differential cyanosis of a very unusual distribution. The cyanosis involved the skin of the entire body with the exception of the right upper quadrant. Report of Cases Case1.—A white boy was admitted to the hospital at the age of one day because of cyanosis and rapid respirations. At birth, the infant did not breathe for five minutes and was cyanotic. Once respiration became established, it remained rapid; his color improved, but cyanosis was noted several times during the first day. His weight was 8 lb. 4oz. The temperature was 100 F. The pulse rate was 160, and the respirations were 36 per minute. No blood pressure could be obtained in the arms or legs. No cardiac murmur was