Rh/ZrO2 catalysts prepared by impregnation of ZrO2 obtained by using the sol-gel method were characterized and used in the combustion of CH4. It was found that specific surface area, porosity, crystalline phases, metal dispersion, surface acidity and surface composition depend significantly on the experimental variables of preparation. The activity in the combustion of methane is affected by the metal dispersion, state of oxidation of the metal component and the presence of chlorine ions in the catalysts. Higher metal dispersion and the presence of Rhd+ species improve the catalytic activity. Conversely, the presence of chlorine ions inhibits, to a certain extent, the catalytic activity as a consequence of partial blocking of the active sites.