University of Wisconsin (UW) preservation solution has been reported to be beneficial for canine organ transplants and for human liver and pancreas transplants. To examine whether it affects renal graft survival, a randomised multicentre trial was conducted to compare its effect with that of EuroCollins solution on delayed graft function, renal function, and patient and graft survival in 695 recipients of cadaveric renal transplants. 352 kidneys were preserved with UW and 343 with EuroCollins solution. Delayed graft function occurred in 23% of the UW group and in 33% of the EuroCollins group (p = 0.003). Three factors other than type of preservation fluid were associated with a higher incidence of delayed graft function: older donor age, intracerebral haemorrhage in the donor, and oliguria in the donor. Renal function as indicated by serum creatinine concentration was better in the UW than in the EuroCollins group. Patient survival in the UW and EuroCollins groups after 1 year was 95% and 94%, respectively. In both groups, delayed graft function reduced 1-year graft survival by 15% (p = 0.0001). 1-year graft survival of UW-preserved kidneys was 6% higher than that of controls (88.2% vs 82.5%, p = 0.04). Delayed graft function is significantly associated with a reduction in 1-year graft survival. The preservation solution is the most important factor influencing development of delayed graft function, and UW solution is superior to EuroCollins solution in reducing occurrence of delayed graft function, improving graft function, extending graft survival.