We report a severe case of cytomegalovirus (CMV) esophagitis in a renal transplant recipient presenting as acute esophageal necrosis (AEN, 'black esophagus'). AEN is an uncommon entity that is a result of mucosal necrosis and has been described only a few times previously. To our knowledge, this is the first report of AEN due to a CMV infection. The disease was manifested by abdominal and epigastric pain, thrombocytopenia, leukopenia, and elevated liver enzymes. Upper endoscopy showed acute esophageal necrosis. Ganciclovir therapy was initiated immediately and resulted in a complete remission of symptoms. We conclude that the possibility of CMV infection should be suspected in any patient presenting with cytopenia, elevated liver enzymes, and epithelial gastrointestinal lesions in the first 6 months after transplantation, and that early viral detection and antiviral therapy can be lifesaving.