In a large metropolitan general hospital, a high incidence of congenital hypertrophic pyloric stenosis was noted in non-Caucasian groups. Bile-free emesis was consistently reported, and admission was frequently delayed. A prompt diagnosis following admission was not always possible. Unequivocal palpation of a right upper quadrant mass was successful in less than half of the patients in this series, and radiographic studies were helpful in establishing the proper diagnosis in the remainder. Liver fracture can occur with improper abdominal palpation techniques. Despite a surprisingly high complication rate, the ultimate result of operative therapy is uniformly excellent. Three patients not operated upon who were followed for more than two years still have evidence of gastric dysfunction. Postoperative emesis following adequate operation is not unusual, occurring approximately one-third of the time. When postoperative emesis is protracted, incomplete pyloromyotomy should be considered.