The clinical effects of combination chemotherapy with 5-FU, ADM plus CDDP for advanced carcinoma of the stomach were evaluated in a prospective randomized and controlled study. Seventy-seven patients from 18 major hospitals were randomly divided into A group and B group using the envelope method. A group was treated with protocol I (5-FU 270-300 mg/m2 iv from the 1st day to the 5th day and ADM 25 mg/m2 iv on the 5th day), and B group was treated with protocol II (5-FU, ADM plus CDDP 70 mg/m2 iv on the 1st day). These protocols were repeated every 3 weeks and repeated 3 courses in principle. Thirty-three cases from A group and 32 cases from B group were available for evaluation. The prognostic factors were compared between A and B group. No difference could be observed between the two groups. No cases from A group were interpreted as PR, while 6 cases (19%) from B group were recognized on PR after 3 courses. The response rate of the overall 19 cases from A group was 0%, while that of the overall 18 cases from B group was 33%. The statistical difference was observed between the two groups. However, no significant difference for the 50% survival time was observed between the two groups. One patient showing PR survived for 28 months. Gastrointestinal disturbances were observed in 60% and leukopenia plus thrombocytopenia in 40% of each group. Frequency and grade of the side effects were not significantly different between A and B group.