During the course of any transplantation procedure, a period of ischemia is inevitable. When living donors are used, as in the clinical situation, the ischemic interval usually can be kept short enough so that minimal damage occurs in the donor organ. However, the use of cadaver organs introduces longer periods of ischemia and therefore poses a more serious problem. Only when maximal organ viability is maintained during the preterminal period and successful storage during an ischemic environment is realized can the routine use of cadaver organs for human transplantation procedures be justified. Previously we reported successful in vitro preservation of canine kidneys,1hearts,2and isolated bowel (ileal) segments3for 24 hours at 2 C and 3.0 atmospheres absolute (atm) of oxygen and for 48 hours (hearts, bowel) at 2 C and 8.0 atm of oxygen.4,5The clear observation that extension of viable storage of these organs