Dynamic free response of thin rectangular plates subjected to steady state one dimensional and two dimensional temperature distributions satisfying the Laplace equation is analysed in this paper by using the finite difference method and finite element method. The governing equations of motion derived by the finite difference method are solved by a simultaneous iteration technique to obtain eigenvalues and eigenvectors. The results of both the methods compare well with those of classical methods in some typical cases. An attempt is made to correlate the non-dimensional frequency parameter and the temperature parameter. Plates of different boundary conditions with at least one edge simply supported are studied. © 1979.