The aim of this study was to evaluate the outcome of patients undergoing endorectal advancement flap repair for perianal Crohn's disease relative to the primary site of intestinal Crohn's disease. From January 1991 to December 1995, 31 consecutive endorectal advancement flap repairs were performed in 26 patients. The results relative to surgical outcomes, length of hospitalization, and recurrence were analyzed. The mean patient age was 40.2 years (range, 16-70). Type of fistulas included: rectovaginal: 20 (64.5%), fistula in ano: 8 (25.8%), rectourethral: 1 (3.2%) and others: 2 (6.5%). The mean length of follow-up was 17.3 (range 3-60) months. The mean length of hospitalization was 3.7 (range 2-5) days. A temporary diverting stoma was created in 6 patients with a 66.7% (4/6) surgical success rate. Twenty-one of the 26 patients had previous procedures consisting of 12 (38.7%) bowel resections, 6 (19.4%) seton placements, 4 (12.9%) drainages, and 6 (19.4%) diverting ileostomies. Eleven patients had multiple procedures. Ultimately, fistulas were eradicated in 22 (71%) cases, including 15 (75%) of the 20 with rectovaginal fistulas and 7 (63.6%) of the 11 with other fistulas. There was no mortality; morbidity included a flap retraction in 1 patient, who required antibiotics for 5 days and bleeding in 1 patient, who required reoperation. Success was noted in 2 of 8 (25%) patients with small bowel Crohn's disease as compared to 20 of 23 (87%) patients without small bowel Crohn's disease (P < 0.05). Endorectal advancement flap is an effective surgical modality for the treatment of fistulas due to perianal Crohn's disease but is less apt to succeed in patients with concomitant small bowel Crohn's disease.