Hormone-resistant prostate cancer (HRPC) occurs when prostate cancer is no longer responsive to hormone therapy. Treatment options are limited, and there is a clear necessity for therapies that improve outcome. Preclinical and clinical evidence supports the role of the immunomodulatory agent lenalidomide in HRPC. In this paper, we report that lenalidomide showed antitumoral activity in a patient with HRPC and bone metastases pre-treated with chemotherapy, decreased the PSA level and improved the patient's health status for the first 5 months. It is important to emphasize that it was not associated with hematologic toxicity.