Small advanced cancers (less than 10 mm in size) have rarely been described in the literature, mainly due to their difficult endoscopic diagnosis. A total of 5120 colonoscopic examinations were performed at the National Cancer Center Hospital East; three cases (0.05%) of small advanced cancer were found. The indigo carmine dye spraying technique with magnifying endoscopy was used for diagnosis. All cases were flat and depressed lesions (8, 9 and 9 mm in size respectively) with V type pit pattern at the magnifying observation. Histology showed three cancers with invasion to the proper muscle layer and two cases of lymph node metastasis. K-ras point mutation was negative in all cases, while p53 stained in two out of the three cases (one diffuse and one focal). It is concluded that small advanced colorectal adenocarcinomas are a reality. Our data on their macroscopic appearance and histology confirm their high malignant potential.