Purpose We investigated the prognostic values of volume-based metabolic parameters by 18F-fluorodeoxyglucose ($^{18}F$-FDG) positron emission tomography (PET)/computed tomography (CT) in gallbladder carcinoma patients and compared them with other prognostic parameters. Materials and Methods We enrolled 44 patients, who were initially diagnosed with gallbladder carcinoma and under-going $^{18}F$-FDG PET/CT. Various metabolic volume-based PET parameters of primary tumors, including maximum and average standardized uptake values ($SUV_{max}$, $SUV_{avg}$), metabolic tumor volume (MTV), and total lesion glycolysis (TLG), were measured in gallbladder carcinoma patients using mediastinal blood pool activity as a threshold SUV for determining the tumor boundaries. Overall survival analysis was performed using the Kaplan-Meier method with PET parameters and other clinical variables. For determining independent prognostic factors, Cox proportional hazards regression analysis was performed. Results Of the 44 enrolled patients, cancer- or treatment-related death occurred in 30 (68.2 %). The mean clinical follow-up period was $22.2{pm}10.4$ m (range, 0.6-35.9 m). Univariate analysis demonstrated that clinical or pathologic TNM stage (P<0.001), treatment modality (P<0.001), MTV (cutoff = 135 $cm^3$, P=0.001), and TLG (cutoff = 7,090, P<0.05) were significant prognostic factors. In multivariate analysis, both clinical or pathologic TNM stage [hazard ratio (HR)=2.019 (I vs II), 21.287 (I vs III), and 24.354 (I vs IV); P=0.001) and TLG (HR=2.930; P<0.05) were independent prognostic factors for predicting overall survival. Conclusions In gallbladder cancer, TLG of the primary tumor, a volume-based metabolic parameter, is a significant independent prognostic factor for overall survival in conjunction with the clinical or pathological TNM stage.