We report a case of cytomegalovirus (CMV) presenting as acute refractory colitis in a patient with a pre-existing 14-month history of ulcerative colitis (UC) who had never previously been treated with corticosteroids or immunosuppressants. A review of existing literature and previous cases of patients with coincident CMV and UC are examined, stratifying these cases based upon absence or presence of corticosteroid use. To date, only five previous case reports of CMV colitis in patients naive to corticosteroids have been described, and only one previous case has had UC diagnosed over 4 wk before the development of CMV colitis. We further discuss the relationship between these two diseases as well as the diagnosis, treatment, patient characteristics, and outcome of CMV infection of the colon in patients with underlying UC. We discuss the need to consider the diagnosis of CMV colitis in patients with refractory UC who are not receiving corticosteroid treatment as well as those who are refractory and are being treated with immunosuppressants and/or corticosteroids.