The results of surgery for anorectal malformation (ARM) in 536 children treated between 1962 and 1993 are presented. Before 1985, patients underwent an abdominoperineal pullthrough for high and intermediate type of ARM, whereas cut-back procedures or perineoproctoplasty were performed in low type. Since 1985, we have changed our policy and performed a modified posterior sagittal anorectoplasty (PSARP) for intermediate type of ARM, eventually combined with an abdominal mobilization for high type. Perineoproctoplasty was reserved for low type of ARM. Data of 143 patients of Group 1 and 85 patients of Group 2 were available for follow-up. Continence was compared using a clinical score. Good or fair continence was found in 82% of patients operated on before 1985 (low type 85% good, 15% fair, intermediate type 17% good, 50% fair, high type 12% good, 37% fair), comparing to 93% in children treated after 1985 according to the new regimen (low type 88% good, 6% fair, intermediate type 59% good, 35% fair, high type 43% good, 47% fair). Liquid stools and inability to retain bowel contents were the main problem in the older series, whereas incontinence could often be attributed to constipation with overflow incontinence in the recently treated group of patients. Analysis of the innervation of fistula and distal rectal pouch in a prospective study comprising 40 of our most recent patients showed normal innervation in only 5% of patients, whereas 66% had neuronal intestinal malformations (NIM) including aganglionosis, NID and hypoganglionosis.(ABSTRACT TRUNCATED AT 250 WORDS)