OBJECTIVE: The aim is to stress the fundamental role of hysteroscopy in the diagnosis of the cause of endometrial pathologies. SUBJECTS AND METHODS: The results of 10 years' experience, between December 1984 and January 1995, in the gynaecological endoscopy outpatients' unit of the Catholic University of Rome are reported. A series of 6180 women undergoing diagnostic hysteroscopy is analysed and the indications, contraindications and side-effects of hysteroscopic examination are discussed. RESULTS: Outpatients, mean age of 51 years (range 22-81), who underwent hysteroscopic examination had, as main indication, abnormal uterine bleeding(AUB). The differing distributions of hysteroscopic findings in pre- and postmenopausal women is stressed, along with the importance of focal endometrial pathologies such as polyps and submucosal myomas in premenopause, the high incidence of endometrial atrophy, and the significant occurrence of hyperplastic and neoplastic hysteroscopic findings in the postmenopause. Primary and secondary infertility are, after AUB, the second most common indications for hysteroscopic examination, and the role of malformation(septate and subseptate uterus), inflammation (intrauterine synechiae) and focal endometrial pathologies (polyps and submucosal myomas) is illustrated. CONCLUSIONS: As a result of the introduction of hysteroscopy it is now possible to preserve organs, with the slight trauma of noninvasive treatment, rather than using extirpartive surgery. In premenopausal women with AUB (n = 2132) the most frequent pathologies were low-risk hyperlasia (25.3%), submucosal myoma (24.5%) and endometrial polyps (8.3%); there were normal findings in 40.2%. There is a low incidence of high-risk hyperplasia(0.7%) and neoplastic pathology (0.5%). In postmenopausal women with AUB there is a high incidence of atrophy (23%), whereas high-risk hyperplasia and neoplastic pathology are five and eight times more common, respectively, in these women than in premenopausal patients.