PIP: Thirty years ago, the International Committee for Contraceptive Research of the Population Council began sponsoring research into a long-acting implantable contraceptive device. Several progestins were considered for application in such a device, but levonorgestrel was ultimately chosen due to the nature of its pharmacodynamics, its high efficacy, and its low incidence of side effects. More than 60,000 women participated in worldwide clinical trials using levonorgestrel in implantable silastic rods, making Norplant the most thoroughly studied contraceptive agent prior to release upon the general market. US Food and Drug Administration approval was granted in December 1990, and since 1991, approximately one million US women have had the implants inserted and more than three million women worldwide have used Norplant. Norplant is marketed in the US by Wyeth-Ayerst Laboratories and the silastic component of the system is manufactured by Dow Corning. The author discusses Norplant's mechanism of action, pharmacokinetics, effectiveness, legal challenges, side effects, other specific concerns with Norplant, continuation rates, insertion, removal, removal techniques, patient selection and counseling, and the future, and notes that the device still faces challenges four years after its introduction.