The development of the University of Wisconsin (UW) cold storage solution has extended safe preservation of the liver and pancreas from 6 to 24 hours or more. From May 1987 until November 1991, 288 livers and 163 simultaneous pancreas/kidney transplants were performed using UW solution. The mean preservation times were: liver, 12.7 +/- 4.4 hours, pancreas 17.2 +/- 4.4 hours, and kidney, 19.2 +/- 4.3 hours. Included in this series were 35 reduced-sized liver transplants, 7 cluster transplants, and 132 combined liver/pancreas retrievals. No differences in allograft function or graft-related complications were seen in organs preserved for less than or longer than 12 hours or in grafts from combined liver/pancreas retrievals. All pancreas/kidney transplants and most liver transplants were performed semi-electively. Actuarial 1-month patient and graft survival after liver transplantation was 91.4% and 80.2%, and at 4 years was 74.0% and 62.0%, respectively. After pancreas/kidney transplantation, the actuarial patient survival at 1 month and 4 years was 99.4% and 90.5%, respectively, whereas pancreatic and renal allograft survival at 1 month was 97.5% and 96.8%, and at 4 years was 83.0% and 83.4%, respectively. The ability to extend preservation times with UW solution has many advantages; however, the most important contribution of UW solution to clinical transplantation has been the increased utilization of scarce donor organs for more recipients because the previously imposed constraints on preservation time have been removed.