The cholecystectomy results in change of cholic acids flow into intestine. Permanent type of the bile flow provokes the increase of proliferation of colic epithelial cells and increases the risk for development of right-sided colorectal tumors. Meanwhile morphological features of colorectal tumors at the patients with cholecystectomy are still remaining to be clarified. The goal of the study was to investigate immunohistochemical markers of proliferation and apoptosis in colorectal adenomas and adenocarcinomas at the patients with cholecystectomy. Fifty patients (40 with retained function of gallbladder and 10 patients with cholecystectomy) histologically diagnosed as proximal colon adenoma or adenocarcinoma were included into the study. Colonoscopic biopsies have been taken from the lesion in cancer patients, and colonoscopic polypectomy has been performed for adenomas. In addition, biopsies have been taken from the adjacent healthy colon mucosa at least 5 cm from the lesion in each patient. 83 tumors and 49 samples of mucosa were immunostained with monoclonal mouse anti-human p53 protein (Dako) and monoclonal mouse anti-human Ki-67 antigen (Novocastra). The index of Ki-67 expression in healthy colon mucosa at the patients with cholecystectomy was 37,5 +/- 1,8% (p < 0,05) as compared to 31,36 +/- 1,9 at the patients without cholecystectomy. No significant difference was detected in the comparison of Ki-67 expression levels between the healthy mucosa and adenomas at the patients with cholecystectomy 43,4 +/- 3,45 (p > 0,05), but more prominent increase was revealed in adenocarcinomas 64,33 +/- 7,67% (p < 0,01). Protein p53 expression in healthy mucosa at the patients with a cholecystectomy was at the same level as at the patients without cholecystectomy (37%). At the patients without cholecystectomy the frequency of revealing p53 in adenomas does not vary, compared with healthy mucosa, however in adenocarcinomas p53 was not revealed at none case. As a contrast, in group of the patients with cholecystectomy the frequency of revealing p53 in adenomas is considerably increased (up to 80%), and even in adenocarcinomas, p53 was revealed in 30,8% of cases. Thus, in benign colorectal tumors at the patients with retained function of gallbladder intensifying of epithelial cells proliferation is not accompanied with intensifying of apoptosis, and in malignant tumors a complete supression of apoptosis is observed. At the patients with a cholecystectomy, the increase of proliferative activity is accompanied by increased apoptosis in adenomas and maintained apoptosis in adenocarcinomas. The retaining of apoptosis in colorectal tumors compensates intensive proliferative activity with expectation of better prognosis.