In this clinical report, occurrence of a spontaneous lymphoma was discussed in a Golden hamster. Male hamster was referred to the veterinary hospital with a history of anorexia, diarrhea, prominent swelling of cervical lymph nodes and progressive weight loss since two weeks ago. During physical examination generalized lymphadenomegaly and severe dehydration was seen. Intraperitoneal dextrose and hydrocortisone was injected but the patient died. In necropsy, significant enlargements of all superficial lymph nodes were observed but the mesenteric lymph nodes, spleen, and liver were seemed normal. Dissected lymph nodes showed necrotized center. Histopathologic examination revealed lymphoid cells containing large vesicular nuclei with evident nucleoli which showed moderate mitotic index. On the basis of these findings, a definitive diagnosis of non-Hodgkin diffuse large B-ceIl lymphoma was made. Experimentally induced lymphomas have been reported in laboratory animals; however, spontaneously occurring lymphomas have been infrequently described in hamsters. This clinical report describes the clinical and histopathological aspects of a spontaneous lymphoma.