CdO films, belonging to the transparent conducting oxide family which has great application potential in photovoltaic solar cells, were deposited onto glass substrates at a substrate temperature of 300 +/- 5 degrees C by an ultrasonic spray pyrolysis technique. The electrical, optical, structural and surface properties of all the deposited films were investigated, and the effect of Mn incorporation (at 2% and 4%) on some physical properties of the CdO films was presented. The films displayed good electrical conductivity and optical transmittance in the visible region of the spectrum. Structural, morphological and elemental analyses of the films were characterized using x-ray diffraction patterns, scanning electron microscopy and energy dispersive x-ray spectroscopy, respectively. The investigations showed that CdO and CdO:Mn films can be suitable materials for optoelectronic applications, especially as transparent contacts for photovoltaic solar cells.