Results of a retrospective analysis aiming to investigate whether microbial translocation occurs in colorectal cancer patients and to evaluate the usefulness of PCR for diagnosis of such translocation in the blood of these patients before treatment initiation. The secondary objective of the study was the correlation of the presence of previously investigated by our group toll-like and vitamin D receptor gene polymorphisms with the detection of microbial DNA fragments in the blood of colorectal cancer patients. The detection of microbial DNA fragments in CRC patients highlights the role of these microbes in cancer development, progression and patients’ survival. Clearly, this increased risk in colorectal patients should be taken into consideration by the clinicians when planning any surgical intervations or during chemotherapy