Colonoscopy, as an established endoscopic procedure in adults, is thought to be of great value in children and juveniles as well. The main indications for its use are intestinal hemorrhage, polypectomy, diarrhoea of uncertain origin, uncertain x-ray findings as well as the confirmation of a diagnosis made by biopsy. The choice of instruments used, preparations prior to the examination and premedication are dependent upon the child's age. 32 children, aged between 1--14 years, and 41 juveniles between 15 and 18 years were examined. Most common diagnoses were Crohn's disease (29), polyps (7) and ulcerative colitis (4). Others were unspecific colitis (3), follicular hyperplasia of the terminal ileum (2), lymphangiectasia (2), one hemangioma and one rectal ulcer. In 24 patients endoscopy revealed nothing pathological within the colon. Examinations should be performed only by skilled endoscopists with special experience of the problems of colonoscopy in children.