The present investigation was planned to study the current status of operation for gastric cancer in Japan, and to find measures to improve the operative results. 3, 492 patients with gastric cancer, who were treated in the period of 4 months from October 1967 to January 1968 in 220 hospitals in Japan, were analyzed. The total number of operated cases was 3, 340 cases, of which 2, 659 had gastric resection. However, curative resection was carried out in 1, 613 cases, the curative resection rate being 48%. The factor most responsible for non-curative resection was peritoneal dissemination. Of 3, 340 operated cases, 530 cases were in the stage I (16%), 696 cases stage II (21%), 949 cases stage III (28%) and 1, 165 cases stage IV (35%). The causes of delay of treatment for gastric cancer were found in 2, 177 (67%) of 3, 242 general cases. The patient was responsible for the delay in 24%, the doctor was responsible in 32%, both patient and doctor were responsible in 6% and both were not responsible in 38%. The curative resection rate was 51% in the prefectural capital cities, 27% in the countries, 70% in the cancer hospitals and 51% in the university hospitals. In this survey, 250 cases were detected by mass gastric examination. The discovery rate of cancer localized to mucosal and submucosal layers by this method was 39%, and in these cases the resection rate was 97% and the curative resection rate was 80%. And, the cases in the stages I and II were 68%. 72% of these cases were symptomless. In conclusion, it is evident that the detection of gastric cancer in early stage is the only way to improve the operative results. Mass gastric examination and establishment of detection clinic, where thorough gastric examinations can be easily carried out, are recommended.