Background: The association of colorectal cancer with human cytomegalovirus (HCMV) is a controversial issuein cancer research. This study aimed to identify the HCMV virus in colorectal cancer tissues and to investigatethe association of HCMV with colorectal cancer. In this study, 50 cancer tissue samples and 50 samples withoutcolon cancer were studied in order to identify the HCMV virus through nested-polymerase chain reaction. Thevirus was identified in 15 cases of colorectal cancer tissues (15/50) and in 5 cases of normal tissues (5/50). Eightcases of adenocarcinoma tissues were in a moderately differentiated stage, and 7 cases had well-differentiatedstage tissues that were positive for viral DNA. The findings were statistically evaluated at a significance levelof p<0.05. The HCMV virus could play a role in creating malignancy and the progress of cancer through theprocess of oncomodulation.