In order to compare the efficacy of simple hypothermic preservation of cadaver kidneys in Collins solution with preservation by pulsatile perfusion, data were gathered on over 1000 transplants between December 1973 and June 1975. In this series of new patient data, it was found that the 1-year thansplant survival rate of 59%+5% in 89 kidneys preserved in Collins solution was significantly better than the 41% + 3% rate found with 358 kidneys preserved by the Belzer machine (p = 0.005). This survival rate was better than the 47% + 3% rate in 421 kidneys preserved on the Waters machine (p = 0.05), and the 34% + 6% rate of 97 kidneys preserved by cold storage in Sacks solution (p = 0.005). The difference in centers probably did not influence the data, since 28 centers submitted data on the Collins-preserved kidneys. In addition, 43 of the 89 kidneys. In addition, 43 of the 89 kidneys stored in Collins solution had been shared between centers.