The dependences of the Seebeck coefficient S on the thickness (d = 5-110 nm) of SnTe thin films grown by thermal evaporation in vacuum on (001)KCl substrates were obtained at room temperature. Distinct oscillations in the S(d)-dependences were observed and attributed to the size quantization effect in SnTe thin films. The monotonic component of the d-dependences of S decreases with increasing thickness. In this connection it is suggested that the equilibrium concentration of non-stoichiometric cation vacancies depends on the SnTe film thickness. (c) 2005 Elsevier B.V. All rights reserved.