As yet, only effective treatment in gastric cancer is early diagnosis and early curative gastric resection. However, almost all cases of gastric cancer, when diagnosed, are advanced cancer and large proportion of them are inoperable because of distant metastasis and peritoneal dissemination. Some half of explorated gastric cancers are unresectable because of extension into adjacent organs or regional lymphnodes. Authors analysed U.G.I. series in 30 cases of unresectable gastric cancer and 30 cases of resected advanced gastric cancer, explorated at Seoul National University Hospital. Results are as follows; 1. In unresectable cases, findings of gastric fixation is observed in 77% and normal in 23%, in contrast to 13% and 87%, respectively, in resectable cases. 2. Retrogastric space is widened in 97% of unresectable gastric cancer and is normal in only 3%, in contrast to 33% and 67%, respectively, in resectable cases. 3. In unresectable cases C-loop widening is observed much mor frequently than in resectable cases. 4. In unresectable cases gastric cancer is more frequent in the body portion, and more frequently infiltrative in type and more extensive in extent in comparison with that of resectable cases. 5. It may be said conclusively, findings of gastric fixation and retrogastric mass are indicative findings of unresectability in gastric cancer.