The use of microwaves to thaw solid organs, viably preserved in the frozen state is intriguing and promising. The objectives of these experiments are threefold: 1) to measure the unknown electrical properties of frozen tissue, 2) to calculate the heating potential distributions of solid organs and to develop equipment to apply microwaves evenly to these organs and 3) to prove that properly prepared frozen solid organs are viable in mammalians. These objectives are to be accomplished by direct measurements of the electrical properties of ice, physiological saline with cryoprotectants, gelatin molds, and frozen mammalian tissue. The thawing equipment will be a meld of commercially available microwave ovens in different frequency ranges and the mammalian test organs will be rabbit and canine kidney.