Mesoporous zinc oxide nanopowders were synthesized by the homogenous precipitation method. Zinc acetate dissolved in water, at different molar concentrations, was used as Zn precursor, whereas ammonium carbonate ((NH4)2CO3) and ammonium hydroxide (NH4OH) were used to prepare the precipitant solutions. The precipitated powders were dried in a conventional drying chamber at 100°C for 1 h, and then calcined at 400°C during 2 h. Crystal structure of powders was determined by X-ray Diffraction (XRD), and the crystallite sizes were calculated from Scherrer’s formula. Morphological characteristics (size and shape) were analyzed from Scanning Electron Microscopy (SEM). The surface area and the pore volume were obtained from BET analysis. The hexagonal wurtzite phase was corroborated in all synthesized powders, irrespective of the synthesis conditions. From SEM micrographs different structures, depending on the experimental routes, were observed. In order to test the sensing properties of the ZnO nanopowders, 10 mm diameter pellets were manufactured and then measured in a propane (C3H8) atmosphere at different gas concentrations and temperatures. Pellets processed from ZnO powders at 0.05, 0.35, and 0.5 M presented the highest sensitivity, 413, 532, at 300°C and 500 ppm of C3H8.