Cytomegalovirus (CMV) infection is a rare event that has been reported mainly in immunocompromised patients who have HIV infection or receive immunosuppressive medication. Although CMV infection is generally asymptomatic in healthy individuals, CMV colitis in immunocompetent host can be potentially severe disease with significant morbidity, especially in older patients. We report a case of CMV colitis complicated by colonic perforation after short term steroid therapy in a patient with eosinophilia who has no evidence of immunosuppression. A high index of suspicion is crucial for early diagnosis of CMV colitis especially in older patients, even though obvious evidence of immunodeficiency is lacking. Colonoscopic examination including multiple biopsies is mandatory for diagnosis of CMV colitis, and antiviral agents should be started once the diagnosis is confirmed. (Intest Res 2007;5:81-86)