The characteristics of early gastric cancer detected by gastric mass survey were examined. The progress of the screening test using the indirect X-ray examination and the tendency toward reduction in mortality from stomach cancer were evaluated. In 1981 the number of examinees in the gastric mass surveys amounted to over four millions in all Japan. From the data of the gastric mass survey in Miyagi Prefecture the rate of detection of gastric cancer was approximately 0.18% and the ratio of early cancer to surgically treated gastric cancer was 59.4% for 1980-1982. Furthermore, the number of m cancer, small cancer and minute cancer cases detected by the survey has increased year by year. These results are due to various advanced screening tests or close examination techniques. From our long-term follow-up study it is clearly indicated that the rate of deaths from stomach cancer in the screened individuals was half of the rate in the unscreened individuals.