This 1-year randomized study was carried out at family-planning clinics of two university hospitals to compare the safety and acceptability of a levonorgestrel-releasing intrauterine system (LNG IUS) and oral contraceptives (OCs) in young nulliparous women. The study population consisted of 200 women aged 18-25 years seeking contraception. Ninety-four women entered the LNG IUS group and 99 entered the OC group. Continuation rates, reasons leading to discontinuation, adverse events, menstrual questionnaires, subjective well-being and sexual behavior were evaluated. Nineteen women (20%) in the LNG IUS group discontinued the study during the 1-year observation period, and 27 discontinued (27%) in the OC group. The most common reason (31%) for discontinuation in the IUS group was pain. In the OC group, hormonal side effects were the predominant medical reason for study termination. The safety and acceptability of the LNG IUS for contraception was observed to be as good as with OCs, with a high continuation rate.