Cytomegalovirus (CMV) is the most common cause of life-threatening opportunistic viral infection in patients with acquired immunodeficiency syndrome (AIDS). However, CMV infection may occur in the immunocompetent individuals. CMV colitis has not been reported in a patient with splenectomy in Korea. Recently, we experienced a case of fatal CMV colitis in a patient with splenectomy. A 69-year-old man complained of bloody mucoid diarrhea and abdominal pain for 2 months. He had the splenectomy 6 months ago. CMV colitis was diagnosed by colonoscopy and pathologic examination. He died of sepsis in spite of antiviral ganciclovir therapy. (Korean J Gastrointest Endosc 2003;26:158162)