WO3 films were prepared by sol-gel deposition process on Corning 2947, microscope slide substrates. The effects of irradiation on the solar parameters of WO3 films were investigated between similar to 1 and 21 kGy absorbed dose by Co-60 radioisotope. Three characteristic optical density bands explained the causes of color due to the absorption of sunlight at induced color centers of the transition elements such as W, Fe and Zr after the gamma irradiation. These bands lead to variations on the solar control in terms of shading coefficient. The absorbed dose plays a key role in the improvement of the shading coefficient dramatically, hence the solar parameters changed considerably depending on the induced color centers of the transition elements and the variations of the grains and the void sizes of the film. The results of the solar parameters of irradiated WO3 films were compared with the unirradiated WO3 films and uncoated coming in the solar range. (c) 2007 Elsevier B.V. All rights reserved.