This case report documents constipation in a Rottweiler secondary to a leiomyoma of the colon. Exposure and excision of the tumor were facilitated by midline laparotomy and extension into the pelvic canal by pubic brim resection and symphyseal separation. Recovery was uneventful. Pre-and post-operative radiographs, a picture of the tumor, and histopathologic section support the documentation.