Missing IUD tails may result from expulsion, retraction of filaments, uterine perforation or pregnancy. Missing IUD tails occur in 5-25% of all IUD insertions, and require a safe and correct diagnostic technique. Plain X-ray with uterine sound in utero is a popular, simple technique which does not require special skills. This study discusses the feasibility and accuracy of this method in 104 women presenting with a history of missed IUD. Twenty women with suspected pregnancy or uterine abnormalities were excluded from the study. The diagnosis was verified by examination of the patient under anesthesia, D & C, laparoscopy or laparotomy. The accuracy rate was 95.23% (80 women). The diagnosis was wrong in 4.76% (4 women) where the X-ray technique wrongly diagnosed intrauterine location of the device, while examination under anesthesia and laparoscopy located these 4 devices in an extrauterine location. Through the use of this technique it was possible to reduce the hospital stay to one day in 95% (80 patients). The technique is feasible, reliable and without complications; it is particularly suitable in hospitals where other diagnostic facilities are not available.