Microwave tempering and infrared assisted microwave tempering of frozen foods were simulated by using finite difference method. The effects of microwave power and infrared power on tempering were discussed. Three different microwave power levels (30%, 40%, and 50%) and three different infrared power levels (10%, 20%, and 30%) were used. The increase in microwave power level and infrared power level decreased tempering times. The change of heat capacity and the dielectric properties of frozen potato puree with respect to time were measured. The temperature distribution inside the sample was modeled, and the predicted results were compared with experimental results. The predicted temperatures showed good agreement with the experimental results. (C) 2008 Elsevier Ltd. All rights reserved.