Nutcracker syndrome should be considered in the case of left ureteric haematuria based on computed tomography with vascular reconstruction of the hilar region of the kidney. The best confirmation is obtained by studying the pressure gradient between the left renal vein and the inferior vena cava during cavography. Various modalities of surgical treatment have been proposed by a few authors, but have been criticised by some authors who question the clinical reality of this syndrome and the efficacy of treatment. The decision to operate may be difficult and other investigations may be useful to confirm the diagnosis. We report the case of a patient in whom the diagnosis of nutcracker syndrome was confirmed intraoperatively by the immediate appearance of massive, reversible haematuria induced by clamping of the renal vein during vein dissection and augmentation plasty. In the light of this original case, we believe that a preoperative percutaneous haematuria provocation test by temporary obstruction of the left renal vein during venography could allow a more formal diagnosis of nutcracker syndrome when this syndrome is highly suspected.