We report the long-term follow-up results of a phase II trial of thalidomide for early-stage multiple myeloma (MM). Patients were eligible if they had smoldering multiple myeloma (SMM) or indolent MM without the need for immediate therapy. Thalidomide was initiated at a dose of 200 mg/day and adjusted as tolerated. Disease progression was defined using modified American Society of Hematology/Food and Drug Administration consensus panel criteria for SMM. Thirty-one patients were enrolled; 29 (19 SMM and 10 indolent MM) were eligible. The median age was 61 years. Median follow-up of living patients was 10.2 years (range, 7.5-11.0 years). Ten patients (34%) had a partial response (PR) and nine had minimal response (MR) for an MR plus PR rate of 66%. The median time to progression (TTP) to symptomatic myeloma was 35 months. Median TTP was 61 months in those achieving PR, 39 months with MR, and 9 months among those failing to achieve either MR or PR, P = 0.005. Median overall survival from diagnosis was 86 months; median survival from onset of symptomatic myeloma was 49 months. Grade 3-4 nonhematologic adverse events were noted in 55% of patients. Randomized trials are needed to determine the role of early therapy in SMM. Am. J. Hematol., 2010. © 2010 Wiley-Liss, Inc.