A case is reported of idiopathic renal arteriovenous fistula in a young adult suffering from arterial hypertension. It was treated by conservative surgery with endo-aneurysmorrhaphy and extra-sinusal clamping of the artery supplying the fistula. The post-operative course was uneventful. Arterial pressure returned to normal after 30 months. Diagnosis, therapy and the relationship between hypertension and fistula are discussed.