Objective This study aims to evaluate the relationships of metabolic fluorodeoxyglucose PET/computed tomography (FDG PET/CT) parameters such as whole-body metabolic tumor volume (WB MTV), WB-total lesion glycolysis (TLG), and bone marrow (BM)-mean standard uptake value (SUVmean) with clinical stage and other prognostic biomarkers in newly diagnosed multiple myeloma (MM) patients. Methods Patients who underwent pretreatment PET/CT with the diagnosis of MM were evaluated retrospectively. The number of focal lesions, WB MTV, WB TLG, and BM SUVmean values were measured on FDG PET/CT images. Clinical stages and prognostic laboratory parameters were recorded the pretreatment period. Results WB MTV and WB TLG values were significantly higher in patients with more than three focal lesions on FDG PET/CT scan (all P < 0.001). According to the Revised International Staging System (R-ISS), all WB MTV, WB TLG, and BM SUVmean values are significantly higher in patients with stage 3 disease than in stages 1-2 (P = 0.027, P = 0.019, P = 0.001, respectively). Serum creatinine level is positively correlated with WB MTV, WB TLG, and BM SUVmean values (P = 0.020, P = 0.004, P < 0.001, respectively). In addition, the beta 2 microglobulin level, an essential biochemical prognostic parameter, was positively correlated with the BM SUVmean value (P = 0.013). Conclusion The BM SUVmean, WB MTV, and WB TLG values, which reflect FDG avid WB tumor burden, are associated with prognostic biomarkers and R-ISS stage in newly diagnosed MM patients. It contributes to the identification of high-risk patients at the pretreatment staging.