Androgen deficiency in the aging male is associated with negative effects on mood and cognition, diminished sexual function, and osteoporosis. The aging of our population, combined with an increased acceptance of medical technology, has focused greater attention on optimizing health during the "golden years." Androgen replacement therapy may remedy many of the deleterious consequences of hypogonadism. This communication reviews the clinical manifestations and diagnosis of androgen deficiency, the inherent risks and benefits of androgen replacement, and the options of testosterone replacement currently available.