Purpose To investigate the diagnostic value of ~(18)F-flurorodeoxyglucose (~(18)F-FDG) PET/CT (positron emission tomography/computed tomography) on multiple myeloma.Materials and Method ~(18)FDG PET/CT imaging findings were retrospectively analyzed in 31cases with multiple myeloma proved by bone marrow aspiration or biopsy from August 2005 to June 2009. Results The PET/CT imaging characteristics were categorized into three types: ① osseous destruction (n=28): Osseous destruction with active metabolism was found in this type combined with no extramedullary organs involvement. The SUV_(max) ranged from 2.5 to 15.4, and the SUV_(arg) ranged from 2.0 to 11.3. ② Extramedullary organ involvement (n=2): Besides osseous destruction, extramedullary organs involvement were detected in this type demonstrating active metabolism in varying degrees. The SUV_(max) ranged from 2.2 to 8.3 and the SUV_(avg) ranged from 1.7 to 6.5. ③ Diffuse bone marrow infiltration (n=1): Diffuse hypermetabolism without osseous destruction was found in the whole body bone marrow with the SUV_(max) of 13.4 and SUV_(avg) of 8.8.Conclusions ~(18)FDG PET/CT can accurately demonstrate the morphology, extent and activity of multiple myeloma, thus facilitating the clinical staging, whereas multiple osteolytic osseous metastases and osseous lymphoma should be excluded for certain cases.