The choice between oral contraceptives (OC) containing 30 or 20 microg of ethinylestradiol (EE) is founded on clinical sign and medical history of the women. Not always a lower dose of EE cause less side effects than an higher dose. Often 20-microg-EE OC induces menstrual cycle alterations and sexual dysfunctions, inducing the women to stop the treatment. Low estrogens concentration have a negative effect on external genital tract, with a consequent vaginal dryness and dispareunia. It is known that OC with 20-microg of EE determine a lower increase of sex hormone binding globulin compared to 30 mg EE and the consequence can be a reduction in antiandrogen effect of OC. OC containing 30 microg of EE have a positive effect on peak in young women, particularly in lean subjects. Moreover, 30 microg of EE induce a better ovarian suppression associated with a lower steroidal production during the week of interruption. Besides, 30-microg-EE OC works well in blocking ovarian cysts formation in women with endocrine dysfunctions like polycystic ovary syndrome or with previous luteal cysts. In conclusion, an OC with 30 microg of EE and an antiandrogen progestin is better than another with 20 microg of EE with the same progestin, because 30 microg of EE have a more powerful antiandrogenic action and guarantee very good cosmetics and endocrine results.