Behçet's disease is a multisystem disorder affecting primarily mucocutaneous and ocular sites although the gastrointestinal, cardiovascular, central nervous and respiratory systems may also be involved. Hulusi Behçet, a Turkish dermatologist, first described Behçet's disease in 1937 and suggested a possible infectious aetiology. The pathogenesis of this condition still remains unclear although it is likely that infection acts as a trigger in genetically susceptible individuals. We report a patient with unusual cutaneous manifestations of Behçet's disease and antineutrophil cytoplasmic antibodies (ANCA) directed against the cytotoxic protein, bactericidal/permeability-increasing protein (BPI). This is the first report of Behçet's disease associated with this autoantibody.