In a multicenter prospective trial, 58 healthy women aged between 35 and 49 years were studied for one year (639 cycles) while taking an oral contraceptive (OC) containing desogestrel 0.150 mg and ethinylestradiol (EE) 0.020 mg. Efficacy, control of the cycle, side effects, complaints, and climacteric symptoms were monitored after 3, 6, 9 and 12 cycles. No pregnancies occurred during the study period. Spotting gradually decreased from 29.3% in cycle 1 to 4.2% in cycle 12, while breakthrough bleeding (BTB) disappeared after cycle 7. One case of superficial thrombophlebitis and 3 cases of minor side effects were registered. With regard to the complaints, breast tenderness, headache, and depression gradually decreased during the study (basal vs. 12-month data: 50.9% vs. 31.2%, 48.3% vs. 18.7%, 39.6% vs. 20.8%, respectively), while nausea disappeared after three months. A significant treatment-dependent reduction of climacteric symptoms was obtained after cycle 3 and this tendency was maintained up to cycle 12. No changes were registered in body mass index (BMI) or blood pressure.