Telomere length was significantly shorter in marrow myeloma plasma cells (MMPCs) than in peripheral blood granulocytes and lymphocytes from patients with MM. Telomere length (TL) was measured in 48 patients who had myeloma cells and peripheral blood granulocytes (PBGs) and peripheral blood lymphocytes (PBLs) available. TL from normal plasma cells (NPCs) from 7 healthy donors and normal PBG (N-PBG) and normal PBL (N-PBL) are also included. The value indicated in each group is the TL median. Results showed significantly reduced TL in MM cells compared with TL in healthy donor PCs (P < .01), and they showed that TL was significantly shorter in marrow MM cells than in granulocytes and lymphocytes from the same person (P < .001). There was no significant difference in TL between the granulocytes and lymphocytes in the same patient or between granulocytes and lymphocytes of patients and those of donors.