The paper deals with finite element analysis of damped modal vibrations Q-factor values determined by taking into account the thermally-elastic damping. Modal properties of square- and ring-shaped MEMS resonators have been investigated by taking into account the layered structure of MEMS and the influence of the geometry of the clamping zone. The calculations have been performed by employing the COMSOL Multiphysics finite element software. The solution method has been verified comparing numerically and analitically obtained damped modal properties of cantilever MEMS resonator. Experimental investigations of Q-factor values have been performed. The comparison of calculated and experimentally obtained resonant frequencies and Q-factor values indicated good agreement of tendencies of change of the quantities against temperature.