We analysed data on 38 patients with gastric cancer aged 30 years and younger who were surgically treated in the Department of Surgery II, Kyushu University Hospital, between 1965 to 1985. These younger patients comprised 2.6% of the total 1,470 patients treated for gastric cancer during this 21-year period. The durations and the kinds of symptoms in the preoperative period varied with the patient. In patients under 30 years of age, the female patients predominated, and in addition, undifferentiated lesions were more common than the differentiated type, tumours were larger, serosal invasion was more prominent, lymphatic involvement was more common, tumours showed infiltrative growth and the rate of peritoneal dissemination was higher. Consequently the survival rates for these younger patients were poor. Detection at an early stage of the disease is mandatory if the survival rates of younger patients with gastric cancer are to improve.