During the period from June 1973 to December 1978, 338 patients with advanced gastric cancer were treated in our hospital. By retrospective grouping, 142 out of 265 patients with tumor resected received postoperative adjuvant chemotherapy (MMC + 5FU + Ara-C), 123 operated alone were taken for comparison. These two groups were similar in: age, sex, location of tumor, mode of resection, histological type, clinical stage and follow-up rate. The results indicated that the 1, 3 and 5 year survival rates of the combined group were much higher than those of the operation only group. Further analysis showed that the supplementary chemotherapy was particularly valid in stages III and IV. In stage III patients, the 5 year survival rate was increased by 27.8%. In stage IV patients, the 3 and 5 year survival rates of the combined group were 16.3% and 9.8% but none survived over 3 years in the operation only group. The authors believe that postoperative adjuvant chemotherapy plays an important role in controlling the micrometastatic and residual cancer foci.