Polycrystalline CdSxTe1-x thin films deposited using a novel procedure based on the close spaced sublimation (CSS) method were characterized through thermoelectric power (α) measurements. The results revealed that these types of compounds present mixed conductivity and that their net conductivity becomes n-type for S concentrations greater than 50% (x>0.5) and p-type when the S content is less than 50%.