We compared eleven patients in whom symptoms of Crohn's disease appeared at age greater than or equal to 65 with a younger group in whom symptoms had appeared earlier. Only 64% of the older patients were initially recognized as having Crohn's disease, as compared with 96% of the younger patients even though clinical characteristics and initial response to medical treatment were similar in both groups. A higher rate of complications occurred in the older group and follow-up data showed that they had higher mortality and a greater need for continuous treatment. We suggest that awareness of Crohn's disease in the elderly is less than in the young; the diagnosis is more often missed despite the similarity of the clinical features to those of younger patients.