 Male hypogonadism is a clinical situation characterized by a low serum testosterone level in combination with a diversity of symptoms and signs such as reduced libido and vitality, decreased muscle mass, increased fat mass and depression. Similar symptoms in combination with subnormal testosterone levels are seen in some elderly men. Low testosterone levels are associated with known cardiovascular risk factors, and men with diabetes and stroke have lower testosterone levels than healthy men. Even though several publications have suggested that testosterone treatment in hypogonadal men may have beneficial effects, it is still uncertain if testosterone substitution in the aging man is indicated. Despite this uncertainty the sale of testosterone has increased enormously the last few years. 