Crohn's disease is a chronic intestinal inflammation which can involve all the gastrointestinal tract, but it prefers the terminal ileum and ascendant colon. It is often associated with autoimmunity systemic findings (oral ulcer, arthritis). Behçet's disease is a systemic vasculitis of the small vessels. Its intestinal involvement causes bleeding diarrhoea until possible perforation. It's not easy clinically to distinguish between Behçet's colitis and Crohn's disease. We describe a case report in which the problem of differential diagnosis is still open after two years from the first findings.