An ex vivo resuscitation of kidney function following substantial post mortem warm ischemia was attempted with the ultimate goal of overcoming the ischemic barriers in organ retrieval for transplantation. The resuscitation technology involved reperfusion at 32 degrees C with an acellular solution to reinstitute oxidative metabolism of sufficient magnitude to restore function after a substantial postmortem warm ischemic insult. The ability to resuscitate renal function at various time periods postmortem was evaluated. Resuscitation parameters included perfusion pressures, vascular flow rates, vascular resistances, restoration of diuresis with concordant urinary creatinine concentrations, and blinded histologic evaluations. The results of this study suggest that it may one day be feasible to resuscitate organs following as much as 2 hr of postmortem warm ischemia for clinical transplantation. An expanded donor pool consisting of allografts resuscitated post mortem from what is now considered to be the "non retrieval donor" could help alleviate the chronic organ shortage. Furthermore, since organs resuscitated ex vivo at 32 degrees C exhibited ongoing metabolism, which was artificially supported rather than inhibited by traditional hypothermia, diuresis was restored. The ability to collect and analyze urine during organ resuscitation and preservation may present the opportunity to assess organ function prospectively.