The objectives of this study were to determine the functional results of ileorectal anastomosis (IRA) and the endoscopical and histological outcome of the rectal stump in 74 patients operated on for ulcerative colitis. Median follow-up was 7.5 years (range 1 to 35). Functional results, as defined by the usual accepted criteria, were good in 80% of patients. The mean daily number of bowel movements was 4.2 +/- 1.6 (SD). Long term endoscopical and histological features improved in most of cases and only 13.3% of rectal biopsies showed the persistence of acute inflammatory changes; 28.4% of the patients had one or more episodes of acute proctitis during the follow-up period, but none of the patients required proctectomy. One case of severe dysplasia was disclosed, leading to proctectomy. A second case of proctectomy was performed in a patient with microrectum. Biopsies performed preoperatively in this case showed the only case of moderate dysplasia found in our population. Provided that the usual contraindications to this surgical procedure are observed, IRA is still a valid option in the surgical treatment of ulcerative colitis.