To evaluate efficacy, adverse effects, and user continuation rate of an etonogestrel subdermal single-rod contraceptive implant. Methods: A total of 417 healthy volunteers of childbearing age were included in this multicenter trial. After implant insertion, the women were followed up during the 3 years of contraceptive action. At each visit, clinical findings, side effects, and bleeding patterns were recorded. Efficacy and continuation rates were analyzed using the Pearl Index and Kaplan-Meier life tables, respectively. Results: The observation period totaled 958.5 woman-years (27.5 months per woman). The Pearl Index score was 0. Side effects were reported by 44.4% of users, but the proportion had decreased to 16.5% by the end of the study. The continuation rate was 61.4% . The most common reason for early discontinuation (in 21.1% of the participants) was menstrual disturbances. Conclusions: Etonogestrel subdermal contraceptive implants demonstrated high efficacy and an acceptable continuation rate. Counseling potential users explicitly about the side effects will optimize patient success with this long-acting contraceptive. To evaluate efficacy, adverse effects, and user continuation rate of an etonogestrel subdermal single-rod contraceptive implant. Methods: A total of 417 healthy volunteers of childbearing age were included in this multicenter trial. After implant insertion, the women were followed up during the 3 years of contraceptive action. At each visit, clinical findings, side effects, and bleeding patterns were recorded. Efficacy and continuation rates were analyzed using the Pearl Index and Kaplan-Meier life tables, respectively. Results: The observation period totaled 958.5 woman- The Pearl Index score was 0. 44% of users, but the proportion had decreased to 16.5% by the end of the study. The continuation rate was 61.4%. The most common (27.5 months per woman) reason for early discontinuation (in 21.1% of the participants) was menstrual disturbances. Conclusions: Etonogestrel subdermal contraceptive implants demonstrated high efficacy and an acceptable con tinuation rate. Counseling potential users explicitly about the side effects will optimize patient success with this long-acting contraceptive.