During 1963 to 1978 colon interposition was performed on 20 children. Early and late mortality accounted for 3 patients and two transplants failed. Of the 15 long-term survivors, subjective results were obtained from 12 patients 12 to 26 years after the reconstruction. Three patients had an excellent subjective result and 9 had a good result. Nine patients underwent esophagogastroduodenoscopy 12 to 26 years after the reconstruction. The endoscopic findings included: marked tortuosity or dilatation (6), pooling of bile or yellow bezoar (3), macroscopic colitis (3), and polyps in the distal anastomosis (2). Only two patients had a straight colon tube without mucosal changes or marked retention. Specimens for histology were obtained in each endoscopy. Colitis was found in 3 patients, 1 patient had gastric metaplasia in the transplant, 1 patient had dysplasia of colonic mucosa and an inflammatory colonic polyp, and in 4 patients histology showed normal colonic mucosa. Flow cytometric samples were obtained from 8 patients. Two showed an aneuploid cell population; the other 6 had normal diploid findings. Because of frequent endoscopic and histological changes, regular endoscopic follow-up of these patients is warranted.