BACKGROUND:Intrauterine devices (IUDs) provide highly effective contraception for women worldwide. Reluctance to insert IUDs in the primary care setting may relate to concern about potential difficulty and complications, particularly in nulliparous women. AIMS:To determine the practitioner, patient and procedural factors associated with abandoned IUD insertion, practitioner-reported difficulty of insertion and adverse events during IUD insertions in the family planning setting. METHODS:This was a prospective study over a 12-month period of consecutive IUD insertions in four family planning clinics across New South Wales and Queensland. Patient, practitioner and device-related factors associated with abandoned IUD insertion, practitioner-reported ease of insertion and immediate insertion-related adverse events were analysed using logistic regression. RESULTS:Of 996 insertion procedures, successful insertion occurred in 95%, and 90% were reported as easy by the inserting doctor, including 80% of those in nulliparous women. Patient characteristics associated with an abandoned insertion were nulliparity (AOR 5.19; 2.49-10.82) or caesarean section-only deliveries (AOR 5.38; 2.58-11.22) and with practitioner-reported difficult insertion, nulliparity alone (AOR 1.98; 1.11-3.54). Practitioners inserting fewer than 100 IUDs over the 12-month study period more frequently rated insertions as difficult (AOR 1.76; 1.08-2.88). Complications occurred in 34 women and were more likely in nulliparous women (AOR 4.51; 2.16-9.39). CONCLUSIONS:Most IUDs can be successfully inserted, even in nulliparous women, in a primary care setting. Referral to a specialist may be appropriate for some women who are nulliparous or had caesarean section-only deliveries, depending on the experience of the practitioner.