During a 1-yr period between September 1993 and September 1994, 74 patients received cadaveric kidney transplants at our institution. Thirty nine (39) kidneys were cold stored (CS), while 35 received pulsatile preservation (PP) on the Water's Mox system using U.W. Machine Preservation Solution. A perfusionist maintained pressure, flows, pH, and osmolality, within accepted ranges. Vasodilators (Regitine, Stelazine, Verapamil) were routinely added to the machine preservation solution. Most kidneys on PP were from marginal donors, or were imported and had associated long ice storage times. The CS kidneys, however, were from "ideal donors" where immediate function (IF) was expected. The kidneys were transplanted using a common protocol by a variety of surgeons. PP was associated with higher IF rates, shorter hospital stay and decreased overall costs. The function of those kidneys was also compared with the mate kidneys, obtained through a telephone survey of the various transplant centers throughout the country. PP was again associated with higher immediate function rates.