A case of multiple myeloma with testicular involvement is rare. We report a 72-year-old male with testicular infiltration as extramedullary disease of IgD λ-type multiple myeloma. The patient received systemic treatment, which included high orchiectomy, anticancer chemotherapy, and radiation therapy for bone metastasis. Eight months after the initial diagnosis, he remains alive. The testis is a rare location for extramedullary disease of multiple myeloma. Testicular involvement of multiple myeloma indicates a poor prognosis. The particular treatment strategy for extramedullary disease in multiple myeloma remains unclear. Testicular involvement of multiple myeloma is reviewed and discussed in this paper.