There are few reports contrasting the clinical characteristics of Crohn's disease in different age groups. We therefore compared retrospectively children and adults with Crohn's disease. 23 children (mean age: 12.8 +/- 2.5 years) and 66 adults (mean age: 27.0 +/- 4.0 years) were studied. Presenting symptoms of abdominal pain and diarrhea were significantly more common in adults, while in children anorexia and weight loss were more frequent. Children tended to present with extra-gastrointestinal tract symptoms as well, mainly anemia and joint involvement. Common symptoms during active disease did not differ between groups, except that weight loss, evident in all children, was found in only 70% of adults. Anemia was present during active disease in all pediatric cases but in only 62% of adults. There were no significant differences between groups regarding disease location, gastrointestinal complications and extra-intestinal manifestations. We conclude that in children Crohn's disease may differ significantly, mainly presenting with nonclassical symptoms, such as anemia and joint involvement. The primary care physician should be aware of these differences.