Spontaneous rupture of the rectosigmoid colon and herniation of the small intestine through the rupture site and eventual evisceration through the anus is a very rare event. In the literature, only 42 cases have been reported. The majority of them occurred in patients with rectal prolapse and one case was reported in association with a third-degree uterine prolapse. We experienced an 81-year-old female patient with rectal prolapse and second-degree uterine prolapse complicated by spontaneous perforation of the rectosigmoid colon and anal evisceration of the small intestine. Segmental resection of the nonviable small intestine, primary repair of the ruptured rectosigmoid colon, and sigmoid loop colostomy were performed, and the patient recovered well. In our patient, both rectal and uterine prolapses cooperatively damaged the anterior wall of the rectosigmoid colon and resulted in perforation. So, rectal and uterine prolapses should be treated before the complication develops. In this patient, uterine prolapse should be treated because of the recurrence of this rare episode.