Objective Twelve cases with small advanced cole-rectal cancer less than 10 mm in diameter were examined. Methods The endoscopic findings and clinicopathologic data of 12 cases with advanced colorectal cancer less than 10 mm in diameter were compared with those larger than 10 mm in diameter. Results Approximated estimation of the macroscopic types were Ⅱ c in 5 cases, Ⅱ a in 3 cases, and I s in 4 cases respectively. As for the distribution of these lesions, there were 5 in sigmoid colon, 4 in transverse colon, 1 in cecum, and 2 in descending colon. No lesions were detected in rectum. Histologic grade at the deepest invasive portion was shown well, moderately, and poorly differentiated in 2, 8 and 1 case respectively and another case with mucinous adenocarcinomas. Lymphnode metastasis was present in 4 of 12 lesions (33% ). This incidence is rather high, as regards to the small size of each lesion. Endoscopi-cally, all lesions accompanied with converging folds and 7 lesions examined by magnifying colonoscope showed V N pit pattern. Conclusion These results indicated that the advanced colorectal cancers less than 10mm in diameter showing similar characteristics with those of superficial depressed type cancer with likely is the precurser of advanced cancer. The findings of converging folds and pit pattern are considered to be the useful indicators for estimating the depth 'of invasion.