A method for preserving transplant organs for extended periods of time has been developed in the transplant organ preservation cooler. The preservation cooler enhances organ viability by maintaining a temperature controlled organ bath and pumping perfusate through the transplant organ. The emphasis on the transplant organ preservation cooler is to provide a simple and portable system which will be powered by boiled off oxygen from a liquid oxygen source. The design of the preservation cooler pump and temperature control system are presented. Results of tests proving the successful operation of the preservation cooler prototype are also presented. / Master of Science