When 58 minute gastric cancers less than 5 mm in diameter from 55 patients were classified into 22 of the single group (minute gastric cancer alone) and 36 of the multiple group (associated with other large gastric cancers), the preoperative correct diagnostic rate by x-ray was 22.7% and 11.1% in the single group and in the multiple group, respectively, with a total rate of 15.5%. The diagnostic rate by endoscopy, aided by endoscopic biopsy, was 95.5%, 13.9%, and 44.8%, respectively. Therefore, it appears that endoscopy and endoscopic biopsy are most efficient diagnostic tools for the detection of such minute gastric cancers. Since the detection of the depressed type (IIc) of minute gastric cancers is considered most significant because of their frequent submucosal invasion, their characteristic endoscopic findings are emphasized: (1) irregular and polygonal shape, (2) distinct depression, (3) clear demarcation, (4) nodular margins, and (5) moth-eaten appearance and abrupt thinning of the mucosal folds.