To compare the clinical and urodynamic characteristics of continent and incontinent women with severe uterovaginal prolapse. Fifty-eight consecutive women with stage III or IV pelvic organ prolapse between June 1998 and December 2001 were enrolled. Each woman had a urinalysis, pelvic examination and urodynamic study and answered a urinary questionnaire. They were divided into clinically continent (n = 20) and incontinent (n = 38) groups. The clinical symptoms and urodynamic results in the 2 groups were compared statistically with the chi 2 test, Fisher's exact test and Mann-Whitney U test. Incontinent women with severe genital prolapse were more likely to report urinary frequency, urgency and nocturia than were continent women (P < .05). However, the incidence of voiding hesitancy was significantly higher for members of the continent group as compared to the incontinent group (P = .002). With respect to urodynamic variables, including detrusor pressure at peak flow, maximal urethral closure pressure and pressure transmission ratio, significantly higher values occurred in the continent group as compared with the incontinent group; they were 38 (range, 12-66) vs. 24 cm H2O (range, 10-49) (P < .01), 84 (range, 39-117) vs. 63 cm H2O (range, 45-84) (P = .033) and 102% (range, 66-135) vs. 66% (range, 14-98) (P = .019), respectively. All other parameters and the incidence of bladder outlet obstruction and detrusor instability did not differ significantly between the 2 groups (P > .05). The results of this study suggest that severe uterovaginal prolapse could produce obstructive symptoms and prevent or reduce urinary leakage, but whether urethral kinking or external urethral compression causes the obstruction remains unclear. More studies on different types of isolated pelvic organ prolapse are needed to elucidate the mechanism, and specific strategies can be developed to aid urogynecologists in their goal of restoring normal anatomy.