Cytomegaly virus infection (CMV) is commonly found in immunocompromised patients. It is difficult to reach a correct diagnosis preoperatively using only clinical data and conventional images, because they are non-specific. We report a case of an elderly woman who presented with post-prandial vomiting, lower abdominal pain and an epigastric mass. After admission, colon barium study showed a fistula between the transverse colon and small bowel. Pathology found CMV infection in the transverse colon with peritonitis. It is suggested that, in case of immunocompromised patients with gastrointestinal complaint, in whom barium enema shows an intestinal fistula, CMV infection should be included as one of the differential diagnoses.