PURPOSE: This study was designed to analyze how often internal rectal intussusception develops into total rectal prolapse. METHODS: Repeated investigations with defecography were performed in 312 patients because of persisting symptoms. In 79 patients who had a rectal intussusception at the first defecography, results of the second defecography and the patients' records were studied. RESULTS: A total of 38 patients had not undergone any surgical treatment of rectal intussusception or rectal prolapse between the first and second defecographies. One of these patients had a rectal prolapse at the second defecography, and another developed a clinical prolapse after the second defecography. CONCLUSIONS: The present study demonstrates that the risk of developing a rectal prolapse in patients with rectal intussusception is small. This risk should, therefore, not be used as an indication for surgery.