Behçet's disease is a systemic vasculitis of unknown origin. It mainly affects young men. Vascular involvement mainly affects the veins and may manifest as deep or superficial thrombosis. Arterial involvement is rare and serious. Arterial thrombosis or aneurysms/false aneurysms can be life threatening in case of rupture. All the arteries in the body can be affected, with widely varying frequencies. Involvement of the renal arteries is very rare. We report the case of a young patient followed for schizophrenia and known to have Behçet's disease, in whom a false aneurysm of the right renal artery was diagnosed during hematuria. He unfortunately refused any type of intervention.