Vanadium pentoxide (V2O5) thin films have been prepared by spray pyrolysis technique. The influence of solution molarity on the characteristics of the V2O5 has been investigated. X-ray diffraction analysis (XRD) showed that, the films deposited at >= 0.1 M were orthorhombic structure with a preferential orientation along < 0 0 1 > direction. Moreover, the crystallinity was improved by increasing solution molarity. The microstructure parameters have been evaluated by using a single order Voigt profile method. The optical band gaps, determined by using Tauc plot, have been found to be 2.50 +/- 0.02 and 2.33 +/- 0.02 eV for the direct and indirect allowed transition, respectively. Also the complex optical constants for the wavelength range 300-2500 nm are reported. At room temperature, the dark conductivity as a function of solution molarity showed the range of 5.74 x 10(-2) +/- 0.03 to 3.36 x 10(-1) +/- 0.02 Omega(-1) cm(-1). While at high temperature, the behaviour of electrical conductivity dominated by grain boundaries. The values of activation energy and potential barrier height were 0.156 +/- 0.011 and 0.263 +/- 0.012 eV, respectively. (c) 2005 Elsevier B.V. All rights reserved.