This report concerns 133 of 377 patients with gastric cancer who underwent curative gastric resection at the First Department of Surgery, Shinshu University Hospital, between January 1, 1967, and December 31, 1975. The effects of surgical treatment and adjuvant chemotherapy were investigated for every depth of penetration into the gastric walls. The 5-year survival rate was 41.7% among patients subjected to gastrectomy and 61.7% among those treated by curative gastrectomy. The 5-year survival rate decreased along with increased depth of invasion. Following surgical treatment, the 5-year survival rate was higher in the patients who underwent absolute curative resection than in those who were subjected to relatively curative resection. Extended radical gastrectomy is needed for patients with the depth of invasion through the muscularis propria. It is necessary to complement chemotherapy for patients with lymph node metastasis who are subjected to relative curative gastrectomy. In the patients with serosal invasion, papillary and tubular adenocarcinoma decreased and poorly differentiated adenocarcinoma increased substantially. The patients with poorly differentiated adenocarcinoma had a poorer prognosis than did those with tubular adenocarcinoma. Some ideas for the treatment of poorly differentiated adenocarcinoma are earnestly hoped for.