The puborectalis muscle sling was evaluated with MRI in 10 pediatric patients who had rectal pull-through surgery for anorectal anomalies. MRI (1.5T) demonstrated the puborectalis muscle equally or better than CT in 5 patients who had both CT and MRI. The amount of puborectalis muscle mass and the location of the pulled-through intestine in relation to the puborectalis sling was well shown with MRI. Our study suggests that MRI can be reliably substituted for CT in the majority of these patients, to assist in planning further surgery for relief of persistent postoperative fecal incontinence.