Osteoporotic fractures in older men (>50 years of age) are common and associated with considerable mortality and morbidity, but osteoporosis in men is under-recognized and undertreated. Secondary osteoporosis is also common in men, and causes include androgen deprivation therapy for prostate cancer, glucocorticoid treatment and alcohol excess. Clinical trials have demonstrated the efficacy of pharmacological osteoporosis treatments in men in terms of increasing BMD and decreasing levels of bone turnover markers; however, few trials have included fracture reduction end points. This Review will consider the pathophysiology of osteoporosis in men and the evidence for testing and treatment. The aims of the Review are to inform clinical practice, to discuss the current evidence base and to highlight the 2012 Endocrine Society clinical practice guidelines on osteoporosis in men.