Cytomegalovirus (CMV) colitis is uncommon in patients who are not gravely immunodepressed. We report a case of fatal CMV colitis in a 54-year-old woman on low dose steroid therapy. She was admitted to hospital after sudden onset of abdominal pain and hemorrhagic watery diarrhea. After 25 days in the hospital, treatment with high dosage of methylprednisolone was started for presumed ulcerative colitis. Her condition worsened and she died 52 days after admission. It is important to recognize CMV colitis as differential diagnosis to inflammatory bowel disease, particularly when the colitis is refractory to immunosuppressive treatment.