Congenital atresia of the esophagus as usually been regarded as an uncommon condition. In 1931, Rosenthal (to) recorded 255 cases from the literature, including a number of his own. Since then numerous additional cases have been published. We recently encountered two examples, associated with tracheo-esophandgeal fistula, within a month. During the previous ten years there had been 12,285 deliveries on the maternity service of Metropolitan Hospital, but among these the records fail to show a single case of esophageal atresia. Nor is it likely that any cases were overlooked, as a very high percentage of autopsies on the newborn is obtained at this institution, particularly in cases with unusual symptoms. The purpose of the present communication is to present our cases, to review briefly the salient clinical and radiographic features, and to describe a new and simple diagnostic procedure-aeroesophagography- for establishing a diagnosis of congenital atresia of the esophagus. A number of excellent reviews have appeared in the American and English literature, notably those of Griffith and Lavenson (3) in 1909, Cautley (2) in 1917, Plass (9) in 1919, Vogt (14) in 1929, Rosenthal (to) in 1931, Mathieu and Goldsmith (8) in 1933, and Lanman (.5) in 1940. Vogt classifies congenital atresia of the esophagus into the following categories: Type 1: Complete absence of the esophagus (extremely rare). Type 2: Complete atresia with no tracheo-esophageal fistula (rare). Type 3A: The upper esophageal segment communicates with the trachea (rare). Type 3B: The upper segment terminates blindly ; the lower communicates with the trachea or with the bronchi near the level of bifurcation of the trachea (the commonest type). Type 3C: Both esophageal segments communicate with the trachea or bronchi rare). Our cases are both of Type 3B (Type 3 of Ballantyne, 1). Case Reports Case 1: R. K., a white male, was born Oct . 1, 1940, after a normal pregnancy and labor. The family history is irrelevant. The infant appeared normal at birth but shortly thereafter drooling and the presence of a large amount of thick, frothy mucus in the mouth and pharynx were observed, and repeated aspiration became necessary to keep the pharynx clear. On the following day the ternperature rose to 101°, the respiratory rate increased, and many medium and coarse râles were heard throughout the chest. A roentgenogram showed consolidation of the upper lobe of the right lung. Regurgitation of all feedings occurred, and several attempts at gavage proved unsuccessful. It appeared, however, as if some of the food was retained when a Breck feeder was used . The pneumonia was considered the sole cause of coughing, respiratory difficulty, and vomiting. Clyses and whole blood transfusions helped to maintain fair hydration, adding to this impression. The persistence of symptoms, however, led to the consideration of esophageal atresia as the underlying condition, and a roentgen investigation was requested. On Oct. 5 a soft rubber catheter was introduced into the esophagus, and under fluoroscopic guidance was passed down toward the stomach.