Pseudoaneurysms represent a well-recognized vascular complication of renal transplantation, but true aneurysms involving the donor renal artery have not been described. We report a patient who had a de novo aneurysm of the donor renal artery 6 years after receiving a cadaveric renal transplant from a child. The aneurysm was repaired successfully, and allograft function was preserved. Histologic evidence confirmed that the lesion was a true aneurysm. Given the potential for graft loss associated with complications of unrepaired aneurysms, we believe that the presence of a true aneurysm in a donor renal artery represents an indication for repair.