Purpose: This study examined whether 15-19 year old IUD users were more likely to experience complications, failure, or early discontinuation than older users and whether there were differences between users of levonorgestrel-containing IUDs (LNG-IUS) and copper-containing IUDs (CuT380A). Scope: Many US providers remain reluctant to prescribe intrauterine devices (IUDs) to teenagers due to concerns about serious complications, despite guidelines from several organizations, including the Centers for Disease Control, stating that they are safe. There is little previous research on the use of IUDs among teenagers, and the results are either conflicting or insignificant. Methods: A retrospective cohort study was conducted using health insurance claims obtained from a private insurance company of 90,014 women who had an IUD inserted between 2002-2009. Logistic regression models were used to estimate the odds of experiencing complications, method failure, or early discontinuation within 12 months of insertion by age group and type of IUD inserted. Results: Serious complications, including ectopic pregnancy and pelvic inflammatory disease, occurred in <1% of subjects regardless of age or IUD type. Women 15-19 years old were more likely than older adults to have a claim for dysmenorrhea, amenorrhea, or normal pregnancy. Overall, early discontinuation did not differ between teenagers and older women. The study concludes that the IUD is as safe for teenagers to use as it is for older women, with serious complications occurring infrequently in all age groups. LNG-IUS may be a better choice than CuT380A due to lower odds of complications, discontinuation, and failure.