PIP: General practitioners, family planning doctors, and gynecologists are frequently faced with the problem of patients whose IUD threads are missing. The problem may be diagnosed by the patient herself, although only about 2/3 of women who practice self-examination are able to feel their IUD threads. Absent threads may otherwise be found at routine contraceptive follow-up or incidently during gynecological examination for other reasons. The incidence of missing threads is uncertain and may vary with different devices but some indication of the frequency is given by the number of referrals to hospital gynecological departments. 40 such referrals to the John Radcliffe Hospital, Oxford, were reported over a 12-month period. At Northwick Park Hospital, Harrow, the authors have seen 35 patients with missing IUD threads over the past 9 months. Probably many other patients are managed without referral.