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Cattle industry is the most extensive human activity throughout the world that favors habitat loss and changes in the abundance and composition of the native biota. The objective of this research was to determine the effect of sheep and goat grazing on the abundance, population structure, body mass and habitat of rodents in the Perote Valley. We sampled three areas: two at different times without grazing (5 and 15 years) and one other with daily grazing. With a monthly trapping program, we sampled two one-hectare plots in each of the three sampling areas using a trapping grid of 36 "Sherman" Traps each, in addition, we sampled the vegetation in order to describe the habitat. We found that rodent richness was not sensible to grazing effect, while plant richness was higher in grazed areas. Plant height was significantly lower in areas with sheep and goat grazing, and plant cover remained almost constant over the sites. Rodent abundance was less in presence of sheep and goats. Rodent weight did not change significantly between sampling sites. Grazing modified the sex proportion favoring females, perhaps due to a reproductive strategy facing the adverse conditions of the grazed sites.