Cytomegalovirus (CMV) infection was described in patients with Inflammatory Bowel Disease (IBD) about 50 years ago. CMV infection may mimic a relapse of IBD. The role of CMV in IBD remains controversial. Of 23 studies during 1999 to 2015, 16 of 23 studies during 1999 to 2015, 16 studies found that CMV had an an unfavorable impact on the disease status where as there was no impact on disease status in 7 studies. Recent literature suggests a way to recognize patients who need treatment for CMV. Patients older than 30 years, those with steroids and immunosuppressant resistance and those needing increase in dose of immunosuppressant drugs need to be investigated for CMV colitis. Histological examination of colonic mucosa (Hematoxylin and eosin, and immunohistochemistry), colonic mucosal biopsy PCR DNA amplification assay and blood PCR for viremia are the diagnostic tests advised for the diagnosis of CMV colitis and CMV infection.