Chronic undernutrition and high-dose daily corticosteroid therapy are well-accepted causes of growth failure in children with inflammatory bowel disease. Occasionally, children are seen with minimal gastrointestinal symptoms but in whom severe anorexia and profound growth impairment are evident. Recent observations that elevated serum levels of tumor necrosis factor-alpha (TNF) in cachexia associated with a number of disease states have suggested a similar possible role in inflammatory bowel disease. Accordingly, we determined TNF levels in 45 children and adolescents with inflammatory bowel disease (18 ulcerative colitis, 27 Crohn's disease) at varying times during their clinical course and compared them to values obtained from a group of 25 children with functional bowel disease. No differences were noted in serum TNF levels between the children with inflammatory bowel disease and the control population. Values were generally within the range of the lower limit of detection of the assay. In the children with inflammatory bowel disease, there was no significant correlation between TNF levels and disease activity or growth parameters. Our observations suggest that elevated TNF levels are not associated with inflammatory bowel disease in children.