Five patients who had undergone renal transplantation 3 months to 23 years ago were operated on successfully for an abdominal aortic aneurysm. In the first case, dating from 1973, the kidney was protected by general hypothermia. In the remaining patients, no measure was used to protect the kidney. Only one patient showed a moderate increase of blood creatinine in the postoperative period; renal function returned to normal in 15 days. All five patients have normal renal function 6 months to 11 years after aortic repair. Results obtained in this series show that protection of the transplant during aortic surgery is not necessary, provided adequate surgical technique is used. Such a technique is described in detail. Its use simplifies surgical treatment of such lesions and avoids the complex procedures employed in the seven previously published cases.