After 6 hours of cold ischemia the quality of lung preservation was assessed in a canine heart-lung transplant model comparing three clinically used methods for lung preservation: donor core cooling by means of extracorporeal circulation (group I); pulmonary artery flush perfusion with either Euro-Collins solution after prostacyclin application (group II); or University of Wisconsin solution after donor pretreatment with prostacyclin (group III). In all cases St. Thomas Hospital solution was used for myocardial protection. Heterotopic heart and orthotopic left lung allotransplantation was performed in three groups of six mongrel dogs each according to the method of lung preservation. After transplantation cardiorespiratory function was assessed at FiO2 of 0.4 for a maximum of 12 hours. After surgery, significantly improved oxygenation of the donor lung was observed in groups II and III, compared to group I (p less than 0.01). Between groups II and III, no significant differences were found in the oxygenation during the first 5 hours, but in the later postoperative course pO2 values decreased in group II although they remained stable on a higher level during the entire postoperative course in group III (p less than 0.05). University of Wisconsin solution for lung preservation in combination with prostacyclin donor pretreatment provides superior postoperative oxygenation of the transplanted lung compared to currently used clinical standards represented by donor core cooling and Euro-Collins flush perfusion.