Many kidneys obtained from cadaver donors undergoing sudden cardiac arrest cannot be transplanted due to the long periods of warm ischemia from the moment of arrest to nephrectomy. A double-ballon-triple-lumen catheter for the rapid in situ preservation of cadaver kidneys has been designed. Used in combination with equipment routinely found in any hospital, it can cool human kidneys in situ to 10-15 C and maintain this temperature until nephrectomy can be performed. Kidenys preserved with this catheter have functioned after transplantation into suitable recipients. This report describes the design and laboratory evaluation of this new device, its clinical effectiveness and technique of insertion.