This paper presents a simple and inexpensive method for estimation of thermal diffusivity of solid materials. It is based on the time delay for applied temperature at one end of a material to reach onto the other side. A resistance-capacitance (RC) model of transient heat conduction has been used for obtaining the thermal delay time expression from the analogous voltage delay time in a distributed RC ladder. The derived expression of thermal delay time depends on the thickness and thermal diffusivity of material. By knowing the delay time and thickness of material, thermal diffusivity can be estimated by the proposed expression. Simulations and experiments have been performed on different materials for estimation of thermal diffusivity. For measurement of temperature, silicon spreading resistance temperature (SRT) sensor has been fabricated. It is ideally suited for present requirement of experiments because of its light weight, small size, moderate sensitivity and linear response in the temperature range of the interest. Copyright © 2005 American Scientific Publishers. All rights reserved.