We report here on a new approach to washing red blood cells frozen with a high concentration of glycerol in a special freezing container. The wash solution consists of a 150-ml volume of 12% sodium chloride and 2 liters of 0.9% sodium chloride-0.2% glucose- 25 mEq/1 disodium phosphate. Both the Haemonetics Blood Processor 115 and the IBM Blood Processor 2991 have been used with this protocol, with similar results. The in vitro recovery of red blood cells frozen with 8.6M glycerol was 89%, and that of red blood cells frozen with 6.2M glycerol was 93%. The 24-hour posttransfusion survival values averaged 88% for eight units of outdated-rejuvenated previously frozen red blood cells washed by this protocol and stored at 4°C for 3 days before autotransfusion.