Reactive systemic or secondary amyloidosis occurs in 1-29% of adults with Crohn's disease, but only sporadic cases of amyloidosis have been recognized in children with inflammatory bowel disease. We therefore have studied operative specimens (ileal, ileocolonic, and colonic) from 46 children (30 with Crohn's disease and 16 with ulcerative colitis) to determine the frequency of amyloid deposits. Sections of bowel, skin, and lymph nodes (n = 940) were stained by Congo red and examined by light microscopy and by polarized light. Amyloid deposits were found in only one of 46 subjects, an 18-year-old girl who had had Crohn's disease for 6 years. Intestinal amyloid deposits, present 16 months before the clinical diagnosis of amyloidosis, were patchy and seen predominantly in the intestinal mucosa. We conclude that amyloidosis is rare in children requiring surgery for Crohn's disease and ulcerative colitis. Examination of Congo red-stained sections can detect even subclinical amyloidosis. The amyloid deposits in our patient, which were both patchy and consistently mucosal, suggest that multiple endoscopic biopsy samples, not necessarily containing submucosa, are sufficient for diagnosis.