Physical methods of stored grain pest management such as microwave radiation can be utilized as a preventive and curative method of pest control. The susceptibility of various lifestages of Tribolium castaneum (Herbst) to microwave radiation was studied by irradiating infested wheat flour at 3 cm flour bed thickness. All the life stages of T. castaneum were irradiated at five different power levels viz., 136 W, 264 W, 440 W, 616 W and 800 W for 20 s. Eggs were more susceptible to microwave irradiation, whereas the susceptibility of grubs, pupae and adults were comparable. Mortality of all the life stages of T. castaneum increased with the increase in microwave irradiation power. Mortality of egg, grubs, pupae and adults were highest at an irradiation dose of 800 W i.e., 100, 96, 80 and 80%, respectively. Standardization of power, depth of flour bed thickness and duration of irradiation will enable the utilization of household microwave oven for the disinfestation of food grains.