An open prospective clinical trial designed to evaluate the efficacy and safety of the combined hormonal oral contraceptive (OC) containing 75 micrograms gestodene plus 30 micrograms ethinyl estradiol was undertaken in a Mexican population. Sixty-nine healthy women of reproductive age took part in the study for a total of 627 woman-months of observation. The combination of gestodene and ethinyl estradiol proved its effectiveness in preventing pregnancy during the study. Side-effects were minimal and regular endometrial bleeding patterns were observed during one year of continuous use of this OC preparation. The discontinuation rate for medical reasons was 11.6% at one year. Among a sample of 10 women, the gestodene/ethinyl estradiol combination did not induce significant changes in the serum concentration of total cholesterol and LDL cholesterol after 12 months of continuous administration. An increase in serum triglycerides and HDL cholesterol was observed; this effect could be attributed to a lack of androgenic and/or the intrinsic estrogenic behavior of gestodene. It can be concluded that this preparation is highly effective as a combined oral contraceptive; it is well tolerated and might offer some advantages with respect to other oral contraceptive combinations in its short- and medium-term impact on lipid metabolism.