Ten patients received kidneys from living, related donors, the transplants having multiple renal arteries; a retrospective analysis of the postoperative Hippuran renograms is presented. All seven kidneys that had the large artery reopened before anastomosis of the smaller, developed scintigram findings suggestive of acute tubular necrosis (ATN) in the region with the more prolonged ischemia. Three similar kidneys with simultaneous recanalization of both renal arteries had normal Hippuran scintiphotos. Electron photomicrographs from upper- and lower-pole biopsies--in one case undergoing sequential revascularization--confirm the development of ischemic changes consistent with ATN in the half of the kidney developing scan findings of ATN.