Some authors divide rectoceles into those with chronic evacuatory difficulty and normal genital position (type 1) and those with associated pelvic organ prolapse (type 2). This study assessed whether there are physiological differences between these two clinical rectocele types. Female patients were assessed by conventional anorectal manometry, vector manometry, parametric assessment of the rectoanal inhibitory reflex (RAIR), and defecography. Subjects included 33 volunteer controls without anorectal disease, 14 patients with type I rectocele, and 26 patients with type II rectocele. Significant differences were noted for resting pressure measurements (maximal resting anal pressure and vector volume) between rectocele types and between type I patients and controls. Significant differences were noted for squeeze parameters (maximal squeeze pressure and vector volume) only between rectocele types. There were minimal differences in parameters of the RAIR, with a reduced slope of inhibition in the proximal sphincter for both rectocele groups and a reduced maximal inhibitory pressure in the intermediate and distal sphincter of type 1 rectocele patients. There were no differences in transient excitation of the pressure wave during the RAIR reflex to account for pressure variations with no measured differences in rectocele depth (type 1, 2.87 +/- 0.7 cm; type 2, 2.84 +/- 1.4 cm) There are few physiological differences between the different clinical categories of rectocele patients based on the presence or absence of associated genital prolapse.