Cadmium oxide thin films were synthesized by spray pyrolysis technique using perfume atomizer at different substrate temperature on (225, 275, 325 and 375°C) glass substrates. Effect of substrate temperature on the growth mechanism and physical properties of the films was investigated in order to find the suitability of them towards optical device applications. All the films were polycrystalline in nature having cubic structure with a preferential orientation along the (1 1 1) plane irrespective of the substrate temperature. Film transparency increases from 78% to 89% with increase in substrate temperature. Optical band gap decreases from 2.55eV to 2.38 eV with increase in substrate temperature. The refractive index dispersion of the films obeys the single oscillator model. The dispersion parameters, oscillator and dispersion energy of the films were calculated to analyze their choice in designing optical devices. A minimum resistivity of 3.57 x 10-4 Ω cm was obtained for the film coated at 375°
