Abstract In the present paper the growth of MoO 3 thin films on common glass substrates are described. The films were prepared by evaporation of a MoO 3 target with a CO 2 laser (10.6 μm), operating in the continuous wave mode. The effect of substrate temperature on the crystallographic structure and electrical properties of MoO 3 thin films was studied. The chemical composition of the different species formed on the films surface was obtained by X‐ray photoelectron spectroscopy (XPS) and the crystalline structure was studied with X‐ray diffraction (XRD). The electrical conductivity of the films was determined using the standard four‐points method. Conductivity of the films varied from de 10 –9 to 10 –5 (Ωcm) –1 in the 300‐600 K temperature range. Arrhenius‐type plots for the electrical conductivity indicate the presence of at least two different conduction mechanisms. The I‐V characteristic curve shows an ohmic behavior only in the 4.5‐60 V range. Outside this interval the I‐V curve has a behavior described by a power law. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)