Preservation of the small bowel by a cavitary two-layer (University of Wisconsin solution [UW]/perfluorochemical) cold storage method was evaluated in the heterotopic rat segmental small bowel transplant model. Simple cold storage UW was effective only for 24-hr preservation. However, the cavitary two-layer method using UW made it possible to prolong preservation time up to 48 hr. Furthermore, without oxygen bubbling, the cavitary two-layer method was not effective for 48-hr preservation. Histologic studies of grafts preserved by the cavitary two-layer method for 48 hr at 7 days after transplantation showed normal architecture of the intestinal mucosa. This study demonstrates that the oxygenation of the small bowel during preservation by the cavitary two-layer method using UW makes it possible to extend preservation time up to 48 hr in the heterotopic rat segmental small bowel transplant model.