Adverse events of steroids such as infections are likely to occur in the elderly patients with multiple myeloma. We examined the efficacy and safety of lenalidomide and prednisolone therapy in which the dosage of steroid was reduced in the elderly patients in Japan. Method We retrospectively analyzed 22 elderly relapsed/refractory and newly diagnosed refractory multiple myeloma patients treated at our hospital between January 2011 and February 2015. Treatment efficacy was assessed according to the International Uniform Response Criteria for Multiple Myeloma and adverse events by National Cancer Institute-Common Terminology Criteria for Adverse Events (NCI-CTCAE) Ver. 4.0 Easy R (EZR) was used for statistical analysis. Result Complete response (CR), very good partial response and partial response was found in 3, 1 and 18 patients, respectively. The overall three-year survival rate was 58% and time to next treatment was 1 year in 49% of patients. The adverse events were leukopenia (G1-2 23%, G3 9%), anemia (32% G1-2 and 18% G3) and thrombocytopenia (14% G1-2 and 9% G3). Non-hematological adverse events included rash (41% G1-2 and 23% G3), peripheral nerve disorder (23% G1-2, none above G3), and G3-4 renal failure in 10%. Infections of G3 occurred in 5%, and there was no deep-vein thrombosis. Conclusion Lenalidomide and low-dose prednisolone can be safely and effectively administered in elderly patients.