Longo's STARR operation is a new surgical technique for the management of obstructive defecation syndrome. A major advantage is the repair of rectocele and intussusception in a single transanal approach. Complications such as bleeding, infection, anal stenosis, and fistulas are known. In the described patient we detected a cavity in the spatium rectovaginale which was lined by rectum mucosa and connected to the rectum as a result of an incomplete resection of rectum wall and dilatation of the stapler suture. Recurrent stool incrustration in the cavity led to preformation of coproliths. We performed a modified Rehn-Delorme operation to resect the cavity. The STARR operation is a technique which should be used carefully and performed only by surgeons with experience and full knowledge of the potential complications.