An apparatus for perfusing an organ or tissue includes a perfusion circuit for perfusing the organ or tissue an oxygenator for oxygenating perfusate that circulates through the perfusion circuit and an oxygen supply device such as an oxygen concentrator or an oxygen generator configured to supply oxygen to the oxygenator. A method of perfusing an organ or tissue includes producing oxygen from a device such as an oxygen concentrator and an oxygen generator supplying the produced oxygen, preferably as the oxygen is produced, to a perfusate to oxygenate the perfusate and perfusing the organ or tissue with the oxygenated perfusate. The produced oxygen preferably has a concentration greater than the oxygen concentration in air.
