Gastric carcinoma is a rare entity in twins at any age. A 31-year old black male presented with a nine-month history of epigastric pain and was found to have cancer of the stomach. His asymptomatic twin was therefore evaluated and also found to have gastric carcinoma. Both patients underwent gastric resection. Pathologically the cancers were similar, although the associated changes of the gastric mucosa showed some remarkable differences. The uniqueness of carcinoma in twins has resulted in extensive utilization of twin studies in an attempt to clarify genetic, environmental and immunological factors in the development of cancer. The results of these studies reported in the literature, however, are inconclusive. Gastric cancer is quite uncommon in the younger population but must be promptly excluded when symptoms doe not quickly respond to usual therapy.