The aim of the study is to evaluate the possibilities of immunohistochemical revealing of colorectal cancer micro-metastases in liver and to determine their prognostic significance. Material et metods. The material of the research was fragments of liver tissue with metastases of 36 patients with colorectal cancer who had undergone resection of liver (main group), and randomly chosen fragments of liver tissue without macro metastases of 18 patients with colorectal cancer who had died in early postoperative period. 5-6 fragments of the liver tissue taken from the margins of the largest macro metastasis with the interval 1-2 cm were investigated in each case. The detection of micro-metastases on the paraffin sections with the thickness of 4 microns was carried out with the use of antibodies to cytoceratin-20. The results showed that micro-metastases in liver in the main group had been found in 75,9%, in the comparative group — just in one observation with accidentally revealed macro metastasis. Correlative analysis showed the direct definite link between the appearance of micro-metastases and the presence of macro metastases in liver. The significance of multimicrometastatic spreading for the development of intrahepatic progression and the worsening of the long term prognosis of the patients with colorectal cancer were noted. Conclusion: the possibility of use cytoceratin-20 for revealing micro-metastases in liver.