Although the pathogenesis of osteoporosis in men is multi-factorial, testosterone is known to play an important role in the maintenance of the male skeleton. This role, however, appears complicated as it may be mediated in part by aromatization to oestradiol. Testosterone replacement therapy improves bone density in men with hypogonadal osteoporosis, particularly if the epiphyses are still open. There is no well-established treatment for idiopathic osteoporosis in men, but testosterone supplementation may prove to be useful. Further studies are required to confirm the safety and efficacy of this treatment in eugonadal men with osteoporosis.