Colorectal cancer (CRC) has the third highest cancer incidence in the world. There is mounting evidence that the intestinal microbiota plays an important role in colorectal carcinogenesis. but there is no information on protozoa of intestinal microbiota except Blastocystis hominis, although data on this issue is scarce. In this study we are going to evaluate the prevalence of intestinal helminthes and protozoa in CRC patients and control group that includes random residents. Patients will be examined before, after surgery and chemotherapy. Parasites and protozoan infection intensity will be estimated by triple coproscopy.