The microwave heating of ceramic materials has been analyzed by solving the equations for grain growth and porosity (Svoboda and Riedel 1992) during the late stages of sintering, coupled with the heat conduction equation and electric field! equations for I-D slabs. Microwave power absorption and heating profiles have been calculated for Al2O3 and SiC in the absence of sintering and calculations have been carried out to study the effect of increasing dielectric loss of Al2O3 as a function of temperature. A comparison of the densification and grain growth for Al2O3 during microwave and conventional sintering indicates that within the framework of the present model, there is no difference between the two heating modes during the late stages of sintering.