From July 1972 to September 1976, 708 kidneys received through the Interhospital Organ Bank, New England were divided into two groups. Both groups were preserved by continuous pulsatile perfusion. Group 1 (308 kidneys) was maintained at a systolic pressure of 60 mm Hg throughout the preservation period. Group 2 (399 kidneys) was perfused at an initial pressure of 60 mm Hg. The pressure was adjusted to 55 mm Hg at 1 hr, then no further adjustments were made. Comparison reveals that group 2 donors were younger and that the kidneys in group 2 were preserved for longer periods that those in group 1. Both groups had an equivalent number of kidneys that were discarded and kidneys that did not function. The incidence of immediate function was higher in group 2 but this difference is not statistically significant. Compared with conventional preservation, kidneys can be preserved at lower systolic and mean pressures without loss of quality, and in fact, may suffer less damage from perfusion.