The aim of the study was analysis of an anal sphincter function in patients before and after surgery for rectal prolapse.Material and methods. Between 1987 and 2005, 49 patients underwent operations for rectal prolapse. The anal sphincter function was analyzed in 17 of these patients. Abdominal approach surgery was performed in 13 patients; this involved rectopexy in 11 and sigmorectal resection in two others. A transanal approach was chosen in four patients, with the Mikulicz technique in two cases, the Delorme procedure in one, and the Altmeier procedure in the remaining case.Results. In all patients who were operated using the transanal approach, we observed some regression in anal sphincter insufficiency. Among the patients operated using the abdominal approach, first degree incontinence persisted in three cases, second degree in five cases, and third degree persisted in four cases. As a result of the surgical treatment of rectal prolapse by rectopexy and transanal approach, we observed a statistically significant increase in the resting anal sphincter pressure; this increase on average reached 58.8 mm Hg. A statistically significant increase in the average maximum squeeze anal sphincter pressure (95.9 mm Hg) was attained after the surgical procedures were performed on patients with rectal prolapse.Conclusion. The results suggest that the improvement of anal function in the control of stool and flatus after surgical treatment for rectal prolapse appears to be the result of an increase in the rest and maximal squeeze pressures of the anal sphincters.