The posterior sagittal approach was used to treat 792 patients with anorectal malformations. From these, 387 cases were evaluated 6 months to 13 years later. Voluntary bowel movements were present in 74.3% of the entire series. When distributed by diagnosis, the percentages varied: 100% in patients with rectal atresia and perineal fistula; 93.2% in those with vestibular fistula; 80.9% in those with bulbar fistula; 71.1% in those with cloacas; 66.7% in those with prostatic fistula, and 15.8% in those with bladder-neck fistula. Soiling was present in 57% of all cases. Patients with voluntary bowel movements and no soiling were classified as totally continent; 40.8% of the series belong to this group. Distributed by diagnosis, it varied from 100% in cases with rectal atresia or perineal fistula, 65.9% in those with vestibular fistula, 34% in those with bulbar fistula, 31.6% in those with cloacas, 26.3% in those with prostatic fistula; none of the patients with vaginal fistula or bladder-neck fistula was totally continent. Constipation was detected in 43.1% of all patients, and was more frequent in those with simple defects. Urinary incontinence was found in 19% of patients with cloacas who had a common channel shorter than 3 cm, and in 68.8% of the patients who had longer common channels. Other patients suffered from urinary incontinence only when they had an absent sacrum or other severe bladder or urethral congenital defects. An accurate diagnosis and evaluation of the sacrum allows us to establish, with reasonable accuracy, functional prognosis in most children. Those with functional disorders must be treated properly medically, to improve their quality of life.