Although 90% of women at risk for unintended pregnancy in the United States use contraception, <1% of these women use the intrauterine contraceptive device. The mechanism of action of intrauterine contraceptive devices has been controversial, but several studies suggest that interference with sperm migration or function and with fertilization may be the most likely mechanisms. More important, there is lack of compelling evidence that the intrauterine contraceptive device acts as an abortifacient. The risk for pelvic inflammatory disease among users now appears to be extremely low, primarily as a result of better selection of candidates. A levonorgestrel-releasing intrauterine contraceptive device may offer some new therapeutic approaches for the treatment of certain gynecologic disorders. Although women who are not at risk for pelvic inflammatory disease or sexually transmitted diseases are appropriate candidates for the intrauterine contraceptive device, it appears that use can be expanded to selected nulliparous women and women with certain medical conditions.