Connective tissue, consisting mainly of collagen and structural glycoproteins, is an important part of the supportive structures of the genitourinary region. Relatively few data have been published with respect to the role of elastin and glycoproteins in pelvic organ prolapse (POP). Connective tissue of the uterosacral ligament in postmenopausal women with and without genital prolapse was compared. Fifty-nine consecutive women referred for hysterectomy were included in the study. The patients had POP or benign gynecological disease (e.g. myoma of the uterus). Tissue samples from the uterosacral ligament were investigated for localization and distribution of tenascin and elastin using immunofluorescence microscopy. Tissue samples of women with prolapse showed a significantly (p<0.001) weaker immunofluorescent labeling of tenascin compared to samples taken from women without prolapse. Tenascin was detectable in tissues of all women with POP, whereas its immunolabeling was decreased in the uterosacral ligament in women without POP. Intact elastin fibers were observed in tissues of all women without POP, whereas elastin was undetectable or sometimes fragmented in the uterosacral ligament in women with POP. Greater amounts of tenascin and lesser amounts of elastin were therefore found in patients with POP. These results suggest that an altered turnover of connective tissue in the uterosacral ligament might be responsible for the presence of pelvic floor relaxation in postmenopausal women. These data indicate a complex architecture of the extracellular matrix in the uterosacral ligaments, with marked differences in tenascin and elastin expression between postmenopausal women with or without POP.