The big challenge of modern medicine is to assure appropriate standard of life for the elderly. The males over 60–65 years of age represent the fastest growing segment of our population. Androgen deficiency is responsible for many detrimental effects on bone, muscle, sexual function and psychological well being. Androgen replacement therapy may remedy many of these consequences. This article reviews the pathophysiology, clinical manifestations and diagnostics of androgen deficiency; benefits and risk of androgen therapy and options of testosterone drugs.