From 1974 to 1978, 53 colonoscopies were performed in 48 children aged from four months to 15 years using conventional fiberscopes. The majority of examinations were performed under light general anesthesia. The main indications were rectal bleeding and inflammatory bowel disease. Accuracy of barium enema in detecting polyps in this group of patients was unsatisfactory. Because of the precision of diagnosis and the possibility of simultaneous treatment of colonic polyps provided by colonoscopy, it was performed without prior radiologic examination in some children with significant rectal bleeding. In children with suspicion of nodular lymphoid hyperplasia of the colon, colonoscopy is the choice for confirmation of the diagnosis. In children with suspicion of inflammatory bowel disease a good correlation was observed between radiologic and endoscopic findings. In these cases colonoscopy should always be performed, preceded by barium enema. Colonoscopy is indicated in cases with doubtful x-rays to contribute to the diagnosis of the etiology of the inflammation and as a follow-up method of investigation in well-established cases of inflammatory bowel disease. © 1979 American Society of Colon and Rectal Surgeons.