Abstract: Objective: To investigate the incidence and risk factors of osteopathia in patients with multiple myelo-ma(MM). Methods: To retrospect 84 patients with MM seen in our department since January 1983. The incidence of os-teopathia in the 84 cases was calculated and several correlation factors were analyzed, including gender, age, seralbumin,seroglobulin, β 2 -microglobulin, M-protein, blood calcium, blood phosphonium, C-reactive protein, uric acid, carnine, ureanitrogen, and plasma cell proportion in bone marrow. Results: 1)The incidence of osteopathia in these 84 patients was83.3%. There were 60.9% patients with osteolysis and 32.8% with pathological fracture. The cranial bone was involved in58.0% patients; the costal bones were involved in 42.0% patients; and the long bones of extremities were involved in20.3% patients. 2)The seralbumin level was 33.13± 6.09g/L in patients with osteopathia and 39± 0.38g/L in patients withoutosteopathia(P<0.05). Theβ 2 -microglobulin level was 8.11± 0.64mg/L versus 0.953± 0.34mg/L(P<0.05). The seroglobulin lev-el was 53.40± 8.39g/L versus 33.09± 0.02g/L (P<0.05). The blood calcium level was 4.86± 0.19 mmol/L versus 1.93±0.37mmol/L(P<0.05). The uric acid level was 392.59± 71.61umol/L versus 242.5± 19.45umol/L(P<0.05). Moreover, the in-cidence of osteopathia was 96.1% in patients with immature plasma cells and 81.3% in patients without immature plasmacells(P<0.05). In patients of IgG type, the average serum IgG level was 6818.64± 822.57mg/dL in patients with osteopathiaand 2425.5± 430.48mg/dL in patients without osteopathia (P<0.05). 3)High globulin and β 2 -microglobulin levels in serumwere risk factors of osteopathia in patients with MM. Conclusion: Osteopathia is a common complication of MM, which ismore frequently seen in phase Ⅱ or phase Ⅲ of MM. Flat bones are frequently involved, often resulting in osteoporosisand osteolysis, and predominantly correlated with tumor burden.