We describe the case of a young woman with Cogan's syndrome and associated Crohn's disease. Systemic disease was manifested by oligoarthritis and valvular involvement. Crohn's disease has previously been described in two cases of Cogan's syndrome. We suggest therefore that Crohn's disease is pathogenetically related to Cogan's syndrome. For both, systemic involvement is characteristic, and immune-mediated mechanisms and vasculitis are thought to play a major pathogenetic role. Furthermore, both respond to treatment with corticosteroids.