Preservation of vascularized organs, such as the liver, is limited to 24 h before destructive processes disqualify them for transplantation. This narrow window of opportunity prevents the performance of optimal pathogen screening and matching tests and possibly results in the need for retransplantation. Numerous problems are associated with freezing and thawing a whole liver while preserving its viability upon thawing, including complicated geometry, poor heat transfer, release of latent heat, and the difficulty of generating a uniform cooling rate. On the basis of our past success with sheep ovaries, we have now applied our novel freezing technique to a larger solid organ, the liver. Whole rat and pig livers were frozen and thawed using directional solidification apparatus, and viability of these livers was tested by means of integrity and functionality in vitro and in auxiliary liver transplantation. The thawed rat and porcine livers were intact and demonstrated >80% viability. Histology revealed normal architecture. Bile production and blood flow following auxiliary transplantation were normal as well. Our encouraging results in applying this novel cryopreservation technique in rat and pig livers suggest that this method may enable better human organ donor-recipient matching in the future.