We report on a unique case of diffuse large B-cell lymphoma of the cecum, which presented as a subepithelial tumor. A 62- year-old woman with abdominal pain underwent a colonoscopy, resulting in detection of a subepithelial tumor measuring 2 cm in the cecum. We performed a right hemicolectomy with diagnostic and curative intent; histological examination and immunohistochemical staining of the resected tumor indicated a diagnosis of diffuse large B-cell lymphoma. The patient achieved complete remission with combination chemotherapy.