This work reports results of a study carried out to improve the optical, electrical and structural properties of CZTS films grown by spray pyrolysis in a one-step process using a precursor solution prepared dissolving thiourea and salts of Cu, Sn and Zn in a solvent constituted by a mixture of dimethyl sulfoxide (DMSO) and acetone. The improvement of the properties of the CZTS films was achieved through a parameters study performed by using a factorial experimental design 2 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> face centered with reply in the central point. Special emphasis was done on studying the influence of substrate temperature (T <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">s</sub> ), carrier gas pressure (P <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">g</sub> ) and spray pulse time (tsp) on the optical, electrical and structural properties of the CZTS films. The study revealed that the t <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">SD</sub> and T <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">s</sub> as well as their interaction are the parameters that most critically affect the above mentioned properties.