This long-term, open-label multicenter study investigated the clinical efficacy and tolerability of a monophasic oral contraceptive containing 20 micrograms ethinylestradiol and 75 micrograms gestodene. A total of 670 women between the ages of 18 and 45 years received the trial preparation over a 3-year period, giving 19,095 evaluable cycles. Of the 670 participants in the study, 75% completed at least 24 cycles with the trial preparation and 46% remained in the study for the full 3 years. One pregnancy occurred during the study which was considered by the investigator to be the result of misuse of the drug, giving an uncorrected Pearl Index of 0.07. Cycle control with the trial preparation was good, especially in women who did not miss any pills. By cycle 3, only 10.2% of women who had not missed pills reported intermenstrual bleeding (scanty or medium/excessive bleeding) and this decreased to 2.3% by cycle 36. The preparation was well tolerated, with a low incidence of unprompted adverse events. There were no clinically significant changes in mean body weight or blood pressure. Over the 3 years of the study, 10% of women withdrew from the study for reasons related mostly to mild adverse events. Results from this study demonstrate that the trial preparation is a reliable and well-tolerated oral contraceptive that provides good cycle control.