Forty one patients underwent ex situ repair of complex renal artery lesions. This series includes 22 males and 19 females, 10 children and 31 adults. Ages of the patients were comprised between 17 months and 70 years. The operated lesions were: --aneurysms of the renal artery and/or of its branches with or without associated stenosis: 16 cases; --spontaneous dissection of the renal artery with extension to the branches: 7 cases; --extensive dysplasia extended to distal branches: 16 cases; --dysplasia of the artery with segmental lesion of the kidney: 2 cases; --reoperation on the renal artery: 2 cases. In all cases, the kidney was exteriorized after transsection of its vessels. It was cooled by perfusion of cold Eurocollins solution. After repair, the kidney was reimplanted either in the lumbar (16 cases) or in the iliac fossa (27 cases). An arterial substitute was used in 32 cases: 26 arterial and 6 venous autografts. No mortality was observed in this series. Two postoperative thromboses occurred leading to kidney loss (4.6%). Segmental thrombosis leading to partial atrophy of the kidney occurred in 3 cases (7%). During the late follow-up, one iterative stenosis was observed and required nephrectomy; two fusiform dilations of venous autografts were also observed. In all other cases (35 patients, 85.3%), repair of the lesion was successful. Ex situ repair must be reserved to: 1) lesions involving several branches of the artery whose repair requires prolonged renal circulatory arrest and 2) lesions profoundly situated in the renal sinus, especially aneurysms, whose repair is difficult by conventional in situ surgery.