In the pathogenesis of acne, androgen hormones play a crucial role. In the treatment of acne, hormonal therapies provide valuable alternatives to standard modalities in selected women. Although numerous factors contribute to the development of acne, the requirement for androgens is absolute and is one that allows for effective treatments in women through inhibition of androgen expression. The two prerequisites for androgen expression at the level of the pilosebaceous unit are the presence of androgen in the form of either testosterone or dihydrotestosterone; and functioning androgen receptors. A third component may be the metabolism of androgen precursors to active androgens within pilosebaceous units. Hormonal treatment of hyperandrogenism (acne, hirsutism, androgenetic alopecia) such as that seen in polycystic ovary syndrome, centers on reduction of circulating androgen levels and androgen receptor blockade. Combination oral contraceptives represent the primary treatment modality for reducing circulating androgens from ovarian and, to a lesser degree, adrenal sources. Newer formulations may also have clinically significant androgen receptor blocking and 5alpha-reductase inhibiting effects. Newer oral contraceptives have high safety profiles and are used widely internationally for this purpose. Androgen receptor blockers currently in use include spironolactone, cyproterone acetate, and flutamide. Androgen receptor blockers are frequently combined with oral contraceptives to achieve optimal results in selected women. In women with adrenal hyperplasia, low-dose corticosteroids may be added to reduce adrenal androgen precursors. Inhibition of enzymes of androgen metabolism in the pilosebaceous unit remain largely investigational in the treatment of acne, although the benefit of 5alpha-reductase (type 2) inhibition is established in androgenetic alopecia in men. This article reviews the essentials of hormonal influence in acne pathogenesis, discusses the hormonal therapies most utilized in the treatment of acne, and the pre-treatment evaluation of women in whom hormonal therapies are being considered.