OBJECTIVE: To compare vaginal anatomy and sexual function after the conventional posterior and anterior sacrospinous vault suspension. METHODS: A retrospective repeated measures cohort study included all 168 consecutive sacrospinous vault suspension procedures between July 1990 and February 1997. The posterior suspension (n = 92) used a posterior vaginal incision and pararectal dissection. Anterior suspension (n = 76) involved an anterior rather than posterior vaginal incision, retropubic perforation, and dissection of a paravaginal-paravesical rather than pararectal space to accommodate the vaginal vault. Two polytetrafluoroethylene (00) sutures anchored the anterior vaginal cuff (for the anterior sacrospinous suspension) or the posterior vaginal cuff (for the posterior sacrospinous suspension) to the ligament. Postoperative evaluation included an examination using the pelvic organ prolapse quantitative system, assessment of vaginal width and axis, and symptom questionnaire. RESULTS: Total vaginal length and apical suspension were slightly greater after the anterior suspension, and recurrent anterior vaginal relaxation was less likely. No differences were found in maximal dilator size or apical narrowing between the two groups. New onset dyspareunia was reported by two subjects in the anterior vault suspension group, and two in the posterior vault suspension group. Three of these four cases of de novo dyspareunia were attributable to either severe atrophy or recurrent prolapse, and none to vaginal narrowing or shortening. CONCLUSION: After anterior sacrospinous vault suspension, vaginal length and apical suspension were slightly increased, and recurrent anterior vaginal prolapse decreased compared with the posterior sacrospinous suspension technique. Upper vaginal caliber and sexual function appear well preserved using either technique.