This study was undertaken to assess the efficacy of mifepristone as a post-coital contraceptive beyond 72 h and up to 5 days in women who found the intrauterine contraceptive device (IUCD) unacceptable. During a 2 year period 219 consecutive women fulfilling the inclusion criteria and presenting late for emergency contraception were approached and offered a choice of methods. Fifteen (6.8%) women wished to have the IUCD fitted, but 204 (93.2%) who found this unacceptable were offered and accepted mifepristone 200 mg. In one woman there was a technical problem fitting the IUCD and mifepristone was administered. Women who had mifepristone were younger (mean age 21.4 versus 26.9 years, P = 0.004) and more likely to be nulliparous (81 versus 25 %, P < 0.001) than the IUCD group. A total of 155 (75.6%) women who had mifepristone and all 14 who had the coil fitted were followed up. There were no true failures in either group. There was one user failure in the mifepristone group, where pregnancy occurred from an act of intercourse subsequent to treatment, giving a crude pregnancy rate of 0.65%. Mifepristone prevented 85% of expected pregnancies. Most women find the IUCD an unacceptable method of post-coital contraception. Mifepristone is an effective late post-coital contraceptive, which can be offered to women who decline the IUCD.