Latin American open government websites have not been compared or benchmarked. However this is key to assess and understand the open government impact on Latin American countries. The purpose of this paper is to introduce a model to assess open government websites and to compare Mexican and Brazilian portals related on open government and transparency practices. The result shows different levels of innovations and similarities on the interpretation of open government budget portals. Our paper will be divided into five sections. The first section will be an introduction where we address our research question and summarize the Mexican and Brazilian context; the second section is a literature review about open government; the third section is a methodology section which proposes the research model and research design; the fourth section discuss the main findings and the last section presents some conclusions and future research.