A 58-year-old male developed epigastric discomfort and high fever in 2010. Complete blood count showed leukocytosis and a small number of atypical lymphocytes. Gastric endoscopy revealed multiple gastroduodenal erosions and ulcers. Biopsy specimens were obtained and pathological examination demonstrated cytomegalic inclusion bodies. Cytomegalovirus (CMV) IgM antibody was positive and CMV DNA was detected with PCR in his blood, leading to the diagnosis of CMV gastroduodenitis. He was treated with intravenous ganciclovir and his symptoms resolved rapidly. It is recognized that CMV gastroduodenitis is extremely rare in immunocompetent hosts but sometimes shows a severe clinical course in elderly patients. The results from our present patient suggest that we should consider CMV infection in the differential diagnosis of multiple gastroduodenal erosions and ulcers. Our data also suggested that anti-CMV medications could be important treatment options for CMV gastroduodenitis, especially in elderly patients.