Objective:The role of allogeneic hematopoietic stem cell transplantation (allo-SCT) for plasma cell myeloma (PCM) is still controversial. We investigated the effectiveness of reduced-intensity conditioning (RIC) allo-SCT in patients with PCM. Patients and Methods:We retrospectively studied a series of 10 PCM patients who underwent allo-SCT using reducedintensity conditioning (RIC) mainly consisting of fludarabine, busulfan, and low-dose total body irradiation from 2001 to 2006 in our single center. Of the 10 patients, 7 received allo-SCT from an HLA-matched related donor, 2 from an HLAmatched unrelated donor, and 1 from an HLA-2-mismatched unrelated donor. Results:All patients showed leukocyte and platelet engraftment. Seven patients developed grade II ― III acute graft-versushost disease (GVHD), and 4 developed extensive chronic GVHD. With a median follow-up of 90 months, the 5-year progression-free and overall survival rates were 34% and 69%, respectively. Six patients survived for more than 7 years after allo-SCT, and 3 of them are currently in continuous complete response (CR). Five of the 6 long-term survivors received allo-SCT from an HLA-matched related donor during the first remission within 10 months after the diagnosis.However, 4 patients who died of transplant-related toxicity or progressive disease received allo-SCT with relapsed disease more than 20 months after the diagnosis. Conclusion:These results suggested that RIC allo-SCT for PCM has the potential to result in a long-term CR if allo-SCT is performed during the remission of PCM in an early period after the diagnosis.