Suboptimal pulmonary preservation with modified Euro-Collins solution (9/90 to 4/91) prompted us to change to University of Wisconsin solution (4/91 to 4/92). Between September 1990 and April 1992, 94 patients received 100 pulmonary allografts (13 heart-lungs, 45 double lungs, 42 single lungs) that were flushed and preserved with either Euro-Collins (n = 30) or University of Wisconsin (n = 70) solution. Selection of donors and procurement and storage of donor lungs were identical. Bilateral single lung transplantation was performed more often in the University of Wisconsin group and resulted in a significantly longer graft ischemic time (University of Wisconsin group; 303 +/- 62 minutes; Euro-Collins group; 260 +/- 62 minutes; p = 0.007, t test). The use of cardiopulmonary bypass was not statistically significantly different. Preservation injury identified by the radiograph on day 1 was more severe (p = 0.036; Mann-Whitney U test) in the Euro-Collins group than in the University of Wisconsin group. In double lung and heart-lung recipients gas exchange of the allografts was evaluated by the arterial/alveolar oxygen tension ratios at nine intervals during the first 72 hours. The mean arterial/alveolar oxygen tension ratio was 0.62 +/- 0.26 in the University of Wisconsin group and 0.46 +/- 0.23 in the Euro-Collins group, but this difference did not reach significance (p = 0.119, analysis of variance). Despite the longer ischemic time, pulmonary preservation achieved by University of Wisconsin solution appears to be comparable with that achieved by Euro-Collins solution.