Background: Identification of risk factors for exacerbation of ulcerative colitis (UC) can be helpful in the prevention and treatment of it. This study aimed to evaluate the epidemioclinical features of the patients with cytomegalovirus ulcerative colitis. Methods: In this cross-sectional study, patients with UC referred to the gastrointestinal ward of Rasool-e Akram and Firoozgar hospitals were selected. After pharmaceutical treatment of ulcerative colitis, both newly diagnosed patients for colitis and patients who did not respond to treatment and returned to the hospital, Underwent colonoscopy, a colon biopsy was performed and a blood sample was taken for active cytomegalovirus (CMV) by ELISA. Tissue samples were examined by PCR. Results: A total of 72 patients with ulcerative colitis (65 recurrent patients) were included in the study. In total patients with colitis, based on serological results, 11.1% of the patients had acute infection and 88.9% had CMV infection in the past, but based on the detection of CMV using PCR, the virus genome was revealed only in 2.8%. In general, the highest rate of CMV tracking was related to cases of pancolitis and the lowest rate was related to proctitis. The rate of CMV was not affected by other variables such as gender, age or Anti-colitis drug protocol.  Conclusion: The rate of CMV infection in patients with ulcerative colitis is directly related to the extent and severity of the disease but may not be affected by the treatment protocol.