Atresia of the gastric pylorus is an extremely rare congenital anomaly. Six cases have been found in the American literature.1-3,5,8,9 A seventh is included in this review. Bennett1 reported the first patient with pyloric atresia in 1937. This was a 7 lb. 3 oz. (3,260 gm.) girl, whose mother had polyhydramnios. There was persistent vomiting after each feeding during the first four days of life, along with small meconium stools. Upper abdominal distention was marked, but a pyloric tumor could not be felt. X-rays demonstrated a huge stomach with no air in the duodenum. Barium failed to pass into the duodenum. A Fredet-Ramstedt pyloroplasty was done for a 1.5 cm. pyloric tumor. The patient died 36 hours after operation. At autopsy, a probe could not be passed from the pylorus to the duodenum or vice-versa. Microscopically, there was a 1 mm. lack of continuity in the lumen of