We present the case of a 77-year-old woman who initially presented 13 years ago to a colorectal clinic with a change in bowel habit and bleeding per rectum over 7 months. These symptoms were attributed to a tubulovillous rectal adenoma which was excised transanally, but recurred five times in 12 years. The most recent endoscopy showed recurrence of the rectal adenoma and a new rectal diverticulum. Diverticula in the rectum are rare and only a few reports of this condition exist in the literature. Repeated surgical resections and endoscopic polypectomies may have caused a weakness in the rectal wall and led to a pseudodiverticulum.