A case of incomplete mucocutaneous Behçet's disease is presented. In spite of weekly to monthly attacks of genital pain for fifteen years, this diagnostic entity had been ignored. We wish to emphasize that Behçet's disease may be the cause of otherwise unexplained genital erosions. A set of clinical criteria according to an international study group serves to establish the diagnosis. Treatment is controversial. This case has been successfully treated with systemic tetracycline for more than six months.