Concern about upper-genital-tract infection related to intrauterine devices (IUDs) limits their wider use. In this systematic review I summarise the evidence concerning IUD-associated infection and infertility. Choice of an inappropriate comparison group, overdiagnosis of salpingitis in IUD users, and inability to control for the confounding effects of sexual behaviour have exaggerated the apparent risk. Women with symptomless gonorrhoea or chlamydial infection having an IUD inserted have a higher risk of salpingitis than do uninfected women having an IUD inserted; however, the risk appears similar to that of infected women not having an IUD inserted. A cohort study of HIV-positive women using a copper IUD suggests that there is no significant increase in the risk of complications or viral shedding. Similarly, fair evidence indicates no important effect of IUD use on tubal infertility. Contemporary IUDs rival tubal sterilisation in efficacy and are much safer than previously thought.