The authors present their evidence for considering torsion of the stomach as a cause for recurrent vomiting in infancy. Since their interest in this possibility was aroused, it has been encountered with about the same frequency as congenital pyloric stenosis. Normally the stomach is fixed at the cardia and the pylorus, and the remainder is suspended freely by the hepatogastric ligament. The authors describe other anatomic relationships which may permit the stomach to be twisted on its longitudinal axis. It is postulated that the twisting may delay gastric emptying, interfere with peristalsis, or perhaps disturb the circulation of the stomach. Diagrams from post-mortem material are provided, illustrating this possibility, and roentgenograms interpreted on this basis are shown. The characteristic symptoms attributed to this condition are vomiting, beginning soon after birth, often projectile, usually occurring daily, and not always immediately after feeding. The diagnosis was made in 54 infants and children, ranging in age from 1 day to 3 years. This number was accumulated in a period of 6 years. In no case was it necessary to resort to surgery, and the symptoms ceased immediately or were much improved when the patient was placed prone, with the upper part of the body lowered, or, alternatively, merely placed on the right side. The condition is said to be well known in adults, but only one reference has been found in the pediatric literature.