The insertion of two different types of intrauterine devices (Multiload 250 and Silver T) has been monitored in 97 patients through systematic exploration by echography and hysteroscopy. Both techniques seem to be highly reliable in spite of the observation of 9% misplacements of the IUDs not detected by echography. In addition, hysteroscopy enables the diagnosis of frequent associated pathology (endometrial hyperplasia, endometriosis, polyps) difficult to diagnose by echography. The present study demonstrates the fact that the ultrasonography confirmation of IUD localization in the uterus was not always accurate.