Although review articles have provided much information on the NORPLANT® system, information on insertion site complications based on multi-country trials has been limited to infection rates. This paper examines 2,674 NORPLANT® acceptors from seven countries who were enrolled and followed for one year. The one-year incidence rates of infection (0.8%), expulsion (0.4%) and local reaction (4.7%) varied widely among countries and clinics within a country. In contrast to previous reports that insertion site complications occur during the first few weeks of use, these data show that a substantial proportion of insertion site infections (34.6%) and implant expulsions (64.3%) were reported after the first two months of use, while 35.7% of local reactions were reported after 4.5 months of use. Of the 16 women with infections who did not have the implants immediately removed, 8 eventually required or requested removal, indicating that the ICCR recommendation for immediate removal in case of infection appears appropriate. An awareness of the frequency of insertion site complications, distribution of the time of onset post-insertion and potential sequelae of complications will aid clinicians in better client counseling and complication management. © 1990.