Excess of androgens in adolescent population is difficult to define. During puberty a physiologic increase in adrenal and ovarian androgens can be observed. Hyperandrogenism should be considered in girls presenting with premature pubarche, unusual or severe acne, hirsutism, androgenic alopecia or persistent oligomenorrhea longer than 2 years. However, most of the signs of androgen excess can occur transiently in puberty. Moreover, ultrasound imaging is not a viable diagnostic tool, as large, multicystic ovaries are a common finding in adolescents. Therefore, hyperandrogenism in adolescent girls can be a troubling problem because of the difficulty in establishing a diagnosis and in prescribing appropriate therapy. The most common causes of clinical hyperandrogenism in teenage population are PCOS, idiopathic hirsutism, late-onset forms of congenital adrenal hyperplasia. Less common causes are iatrogenic, hyperprolactinemia and Cushing's syndrome. Treatment, including oral contraceptives, low-dose glucocorticoids, and antiandrogens, should be chosen according to the adolescent's symptoms and the source of androgens. This should be combined with traditional therapy for the specific dermatologic disorder.