OBJECTIVES: Denosumab is a human monoclonal antibody against receptor activator of nuclear factor-kB ligand (RANKL), which can be used for osteoporosis as an antiresorptive agent.The aim of this study was to evaluate the efficacy and safety of denosumab for the treatment of postmenopausal osteoporosis by performing a meta-analysis.  METHODS: Pubmed, EMBASE, the Cochrane Central Register of Controlled Trials, and other trial registries through July 2014 were searched. Inclusion criteria were randomized, placebo-controlled clinical trials on patients with postmenopausal osteoporosis, 60mg of denosumab every 6 months, consistent time framework, and derivable outcomes for incidences of new vertebral, nonvertebral fractures, and adverse events. A meta-analysis using fixed-effects model was conducted to calculate pooled relative risks with a 95% confidence interval. Heterogeneity across studies was also assessed.  RESULTS: Six RCTs involving 9134 patients were included. The results showed that denosumab was associated with a significant reduction in new vertebral fractures risk (RR=0.325, 95%CI 0.256 to 0.412, p<0.001). A decreased risk of nonvertebral fractures was also observed (RR=0.789, 95%CI 0.670 to 0.928, p=0.004). As compared to the placebo arm, the denosumab arm showed no evidence of significant risk of total adverse events [RR=1.003, 95%CI 0.991 to 1.015], serious adverse events [RR=1.042, 95%CI 0.967 to 1.124], and fatal adverse events [RR=0.785, 95%CI 0.557 to 1.067]. In addition, the incidence rates of all treatment-related adverse events and dropouts due to adverse events were not significant between the denosumab and placebo arms.  CONCLUSIONS: The efficacy of denosumab on fracture risk reduction and its safety has not yet been systematically proved. However, results of this meta-analysis showed that denosumab was associated with a significant reduction in the risk of vertebral and nonvertebral fractures in patients with postmenopausal osteoporosis. No evidence of increased risk in serious, fatal and all treatment-related adverse events were detected.