The article compares the transformation and general reconfiguration of the agricultural sectors of Chile and Mexico in the context of the "role" assigned to them in the development models known as neoliberal, applied since 1973 and 1982 respectively. This paper examines the reasons why similar policies and models have had an unequal effect in the two countries, in which highlight the relatively greater modernization and productive restructuring of the Chilean sector facing to the Mexican. To do so, it is use official statistical data -aggregated and disaggregated- and other secondary sources, which are applied in a multidisciplinary analysis. It is concluded that the different agrarian structures, of classes, and the different historical characteristics of the liberalization and opening process, are keys to explain the main differences.