[en] Full text: Nanostructured materials have been extensively studied, not only for new properties and their possible technological applications, but also for the search for a better understanding of the physical and chemical aspects that cause such changes. The zinc oxide compound was one of the first materials in the form of thin films to be applied as a gas sensor. Although a significant amount of work on the use of ZnO as a sensor has been published in recent years, increasing sensitivity and selectivity towards the detection of certain gas types and their use at a temperature closer to the environment achieved. Different studies have shown that these factors can be strongly affected by changes in morphology, particle size and carrier density, as ZnO semiconducting properties are strongly dependent on the addition of dopants. Motivated by these considerations, in this work we undertook an investigation of the role of Nb, Ce and Cu doping in the gas sensing properties of Zn_1-xM_xO nanostructure thin films, obtained by polymeric precursor method. These films were fully characterized by employing a variety of characterization techniques, which include X-ray diffraction (XRD), micro-Raman spectroscopy, emission scanning electron microscopy (FE-SEM). Regarding its gas sensing properties to oxidizing gases, our results demonstrate that the Ce and Cu doping increase significantly the sensitivity, response and recovery time. Also, we investigate the sensing properties regarding CO detection. (author)