Osteoporosis is a significant threat to aging bone in men. Thirty percent of hip fractures occur in men; during initial hospitalization and the first year after fracture, the mortality rate is twice that of women. Nevertheless, osteoporosis in men is grossly underdiagnosed and undertreated. The most frequent factors associated with osteoporosis in men are age >75 years, low baseline body mass index (<24 kg/m(2)), weight loss >5% over 4 years, current smoking, and physical inactivity. Osteoporosis in men is either secondary to a primary disease or is idiopathic. It exhibits a bimodal age distribution, with peaks at age 50 years (secondary disease) and at age 70 years (idiopathic). Prevention and early detection currently are the best forms of management. Alone or in combination, calcium, vitamin D, bisphosphonates, and human parathyroid hormone are all effective management options. In the acute setting of fragility fracture, the orthopaedic surgeon is key in identifying patients at risk because the surgeon provides primary care and may initiate prophylactic measures to prevent future fractures.