Since 1987, 67 children with ulcerative colitis, 14 with colonie polyposis, and one with Hirschsprung's disease have undergone colectomy and endorectal ileal pullthrough procedures (ERP). Seventy-six children had a lateral ileal reservoir and six had a straight pullthrough. Seventy-seven patients had a diverting ileostomy for 4 months; five polyposis patients underwent ERP without ileostomy. Forty-three (52%) developed complications, including ileoanal stenosis with reservoir outlet obstruction (14), elongated ileal spout (2), elongated ileal reservoir > 15 cm (4), and a combination of outflow obstruction, reservoir enlargement causing stasis (14), and intestinal obstruction causing obstruction (10). Thirty-two children required reoperation. Sixty per cent of complications occurred in the first 30 patients. Only three of the last 40 patients had reoperation. There were no deaths. Four children (two with Crohn's disease) returned to a permanent ileostomy (4.9%); 10 had a temporary ileostomy. Five straight pullthroughs were converted to a reservoir because of stool frequency; 19 underwent reservoir reconstruction because of stasis. Seventy-five children (91.5%) are currently progressing very well. Features for optimal function include a short rectal muscle cuff, a short reservoir and spout, and aggressive correction of rectal strictures. The ERP is a desirable option to proctocolectomy and ileostomy for children with colitis or polyposis.