Although the first cancer to be treated by exposure to roentgen rays was a carcinoma of the stomach, reported by Despeignes (1) in 1896, radiation therapy of carcinoma of that organ has fallen into disrepute. There are many causes for the prevailing pessimism. Ninety per cent of all gastric carcinomas are believed to be insensitive to roentgen rays, though it should be noted that no adequate method exists for determining the radiosensitivity of any individual tumor. The mobility of the stomach makes it difficult for the roentgenologist to direct his cross-fire accurately. The concomitant irradiation of liver, pancreas, and adrenals proved a temporary deterrent. The good general health frequently associated with tumors in other locations, such as the breast and skin, is usually absent in carcinoma of the stomach, and the accompanying cachexia makes these patients less able to stand the radiation sickness, with its attendant nausea and vomiting. Aside from such handicaps, necrosis of a tumor that is radiosensitive may produce perforation and hemorrhage. Many attempts have been made to overcome these difficulties. Holfelder (3) utilized a compression diaphragm in order to reduce the distance between the target and the tumor. Attempts were made to fix the stomach to the anterior abdominal wall prior to irradiation. Scholz (4) recommended barium-filling of the stomach in order to utilize secondary radiation and to protect adrenals and pancreas. In spite of these and other efforts to solve the problem, a deep gloom was manifested by the majority of influential authors, and cancer of the stomach was generally classified as not amenable to irradiation. As recently as 1933, Kaplan (5), in a report of over a thousand unselected cancer cases, briefly dismissed the irradiation of gastric carcinoma as of little value. Pack (6), in his latest monograph on cancer of the esophagus and gastric cardia, discusses radiation therapy of carcinoma of the esophagus by Nielsen's rotation technic, but he does not mention results in carcinoma of the cardia. When evaluating the radiosensitivity of carcinomas of other organs it is not customary to group them together indiscriminately. In spite of repeated attempts, however, no reliable criteria, either gross or microscopic, have been found for predicting the sensitivity of gastric carcinomas. Pack (7), who has written extensively on this subject, utilized the classification of Ewing (2). He describes the bulky adenocarcinoma as being likely to regress under radiation treatment when situated at the cardia or fundus. Carcinoma telangiectatica, a type of medullary cancer or carcinoma simplex, is sometimes sensitive to radiation; it occurs chiefly in the fundus and cardia. The carcinomatous ulcer is described as occasionally radiosensitive, and the anaplastic small-cell gastric cancer as radiosensitive. It is interesting to note that most of these tumors are frequently located in the proximal portion of the stomach.