An organ preservation system having an organ chamber with a perfusate reservoir surrounded by a heat exchanger. The system has a pump for circulating perfusate, which draws perfusate from the reservoir and passes the perfusate through a bubble trap, and temperature and pressure sensors prior to entering the chamber where the organ is perfused. An oxygenator with a platform and a filter is situated within the perfusate reservoir such that perfusate leaving the organ which rests on the platform passes through the filter before dripping into the perfusate reservoir below. The pump re-circulates perfusate from the perfusate reservoir. The oxygenator has gas permeable tubes wound around support legs of the oxygenator. Circulation of oxygen through the tubes allows for gas exchange by diffusion across the membrane to oxygenate perfusate flowing around the tubes.