Lenalidomide (Revlimid®) is an immunomodulatory drug with multiple mechanisms of action against multiple myeloma. It is a thalidomide analogue, with improved potency and reduced toxicity compared with thalidomide. In the EU and USA, lenalidomide monotherapy is indicated for the maintenance treatment of patients with newly diagnosed multiple myeloma who have undergone autologous stem-cell transplantation (ASCT). In the pivotal, phase 3 IFM 2005-02 and CALGB 100104 trials, lenalidomide maintenance therapy after ASCT administered until disease progression significantly prolonged progression-free survival (PFS; primary endpoint) relative to placebo in patients with newly diagnosed multiple myeloma. These results are generally supported by those of the phase 3 GIMEMA and Myeloma XI trials. Lenalidomide maintenance therapy significantly prolonged overall survival in CALGB 100104 but not in IFM 2005-02. However, a meta-analysis of patient-level data from IFM 2005-02, CALGB 100104 and GIMEMA showed an overall survival benefit with this therapy. Lenalidomide maintenance therapy had a manageable tolerability profile in the pivotal trials. Grade 3/4 haematological adverse events and grade 3 nonhaematological adverse events were more common with lenalidomide than with placebo. Lenalidomide increased the risk of a second primary cancer, but the survival benefits outweigh this risk. In conclusion, lenalidomide maintenance therapy after ASCT until disease progression prolongs PFS and overall survival in patients with newly diagnosed multiple myeloma. Therefore, lenalidomide offers a valuable maintenance treatment option for this population.