Hormones exert a pervasive influence on sexual activity. Androgens are involved in the initiation and maintenance of libido and spontaneous arousal. In recent years, the clinical use of exogenous androgens for treatment of sexual dysfunction has received a great deal of attention. Good evidence exists that such treatment is effective for arousal difficulties in men and women in the setting of a hypo-androgenic state. This article reviews the relationship between androgens and sexual function.