Two hundred and sixty-seven cases of gastric carcinoma detected by mass survey included 196 discovered at the first examination (Group A) and 71 noted at the annual sequential examination (Group B) were analyzed in terms of growth pattern and prognosis. The incidence of early carcinoma was 54.9 per cent in Group B higher than 35.7 per cent in Group A. In early carcinoma, the superficially spreading (SUPER) type of carcinoma was more common in Group A than in Group B. On the contrary, the penetrating growth (PEN) type of carcinoma was more frequently found in Group B than in Group A. About eighty per cent of those with an advanced carcinoma, in both groups, was the advanced PEN type. The outcome of the patients in Group B was more favorable. These results support the hypothesis that the majority of advanced carcinoma is derived from the PEN type of early carcinoma. Early detection of the PEN type of carcinoma is mandatory.