Hysterosonography, which consists in the injection of some cc of saline in the uterine cavity during sonography, allows an exploration of the uterine cavity and of the endometrium. Accuracy of hysterosonography is similar to that of office hysteroscopy. Hysterosonography distinguishes normal cavities from pathologic ones, endometrial atrophy from mucosal anomalies, polyps from myomas. Conversely, endometrial biopsy is still necessary for diagnosis of hyperplasia or cancer. Hysterosonography can also be proposed for first trimester bleedings, trophoblast retention or ectopic pregnancy. In the near future it could be applied to therapeutic goals such as sonographic section of polyps.