We report a case of metachronous bilateral malignant lymphoma of the testis. A 67-year-old man was admitted to our hospital with complaints of left scrotal swelling with swelling of the left inguinal lymph node. Left high orchiectomy and dissection of the left inguinal lymph node were done under the diagnosis of the testicular tumor. Histopathological diagnosis was non-Hodgkin's lymphoma of diffuse, medium-sized cells of the B cell type. Several examinations revealed no apparent additional involvement. Chemotherapy was initiated with cyclophosphamide, adriamycin, vincristine and prednisolone (VEPA). One year and 10 months later, contralateral right scrotal swelling with swelling of the right inguinal lymph node occurred. Histopathological findings were similar to those of the resected left testis. We discussed malignant lymphoma of the testis, especially bilateral cases.