Background: Colectomy is the definitive treatment for ulcerative colitis (UC) to remove the inflammatory burden. Crohn's disease, however, can affect any portion of the bowel with a propensity to involve the terminal ileum. In some patients with fulminant colitis, distinction between the two is imperfect. Manifestations of Crohn's after colectomy can be devastating because the ileum is needed for restoration of continuity. There is currently little information in the pediatric literature addressing this concern. Therefore, we reviewed all of our patients who underwent colectomy for inflammatory bowel disease to evaluate the risk of subsequent Crohn's manifestations and to document the outcomes. Methods: A two-center retrospective review of children who underwent colectomy for IBD from January 2000 to July 2010 was performed. Demographic, diagnostic, management, and outcome variables were recorded. Results: We identified 70 patients who underwent colectomy for UC. The mean age at diagnosis was 12 y ± 7 y, and 59% were female. Clinical diagnosis prior to colectomy was UC in 90%, and indeterminate colitis in 10%. There was discordance between clinical and pathologic diagnosis in five patients, two patients were clinically diagnosed with UC but had an indeterminate biopsy, and three patients were clinically diagnosed as indeterminate colitis with a biopsy confirming UC. Indications for colectomy were refractory bleeding in 63%, failure of medical treatment in 28%, toxic megacolon in 6%, and perforation in 3%. A restorative pouch was created after colectomy in 46% using a two-stage approach while, 53% were managed with an initial colectomy and three3-stage approach. In one patient, Crohn's was intraoperatively diagnosed from the operative colectomy specimen. This patient had a clinical diagnosis of UC with concordant biopsy prior to surgery. After total abdominal colectomy, 68 patients went on to ileal pouch anal anastomosis by either a two-stage or three-stage approach. In these patients, nine (13%) had a change in their diagnosis to Crohn's after reconstruction. Crohn's complications requiring an operation consisted of two patients with anastomotic dilations, four patients with fistulotomies, and one patient with perianal abscess drainage procedures. Conclusions: In the children studied, 13% had a diagnostic change to Crohn's disease, and 13% were diagnosed with Crohn's after ileal pouch-anal anastomosis (IPAA). In patients with IPAA and Crohn's, there were more operative interventions for perianal disease. © 2011 Elsevier Inc. All rights reserved.