Globally, one in five men aged >50 years is predicted to experience an osteoporotic fracture. Because of the treatment gap in osteoporosis and the paucity of bone-forming agents for men, new osteoporosis treatments are needed. To evaluate the safety and efficacy of romosozumab in men with osteoporosis. Phase III randomized BRIDGE study (placebo-controlled double-blind study evaluating the efficacy and safety of romosozumab in treating men with osteoporosis; ClinicalTrials.gov identifier, NCT02186171) for 12 months. Thirty-one centers in Europe, Latin America, Japan, and North America. Men aged 55 to 90 years with a baseline bone mineral density (BMD) T-score at the lumbar spine (LS), total hip (TH), or femoral neck of ≤-2.5 or ≤-1.5 with a history of a fragility nonvertebral or vertebral fracture. The subjects were randomized 2:1 to receive romosozumab 210 mg subcutaneously monthly or placebo for 12 months. The primary efficacy endpoint was percentage change from baseline in LS BMD at month 12. In 245 subjects (163 romosozumab, 82 placebo), at month 12, the mean percentage change from baseline in the LS and TH BMD was significantly greater for the romosozumab group than for the placebo group (LS, 12.1% vs 1.2%; TH, 2.5% vs -0.5%; P < 0.001). Adverse events and serious adverse events were balanced between the two groups, with a numerical imbalance in the positively adjudicated cardiovascular serious adverse events romosozumab, 8 (4.9%) vs placebo, 2 (2.5%). Treatment with romosozumab for 12 months increased the spine and hip BMD compared with placebo and was well tolerated in men with osteoporosis.