A total of 50 children with Crohn's disease were examined by barium follow-through and colonoscopy with ileoscopy, to determine the value of small bowel radiology. Of these children, 40 (80%) had evidence of small bowel Crohn's disease on ileoscopy and/or barium follow-through. Twenty-two (44%) had disease confined to the terminal ileum. Radiology diagnosed disease proximal to the terminal ileum in 18 cases (36%), including 5 children in whom the terminal ileum was normal. Ileoscopy was not possible in nine patients (18%), six of whom had small bowel disease on barium follow-through. Colonic involvement, demonstrated in 34 (68%), was the sole site of disease in 6 (12%). Fifteen (30%) children had surgery, which in six (12%) was determined by the radiological findings of complicated small bowel disease. As the terminal ileum may be uninvolved in the presence of proximal ileal disease, normal ileoscopy does not exclude small bowel Crohn's disease. Small bowel radiology remains necessary to assess the full extent of Crohn's disease in children.