The aim of the paper is to present a quantitative analysis of the elections results in the municipalities of Baja California between 1983 and 2013, within the context of Political Opening in Mexico that began in the 80’s. It analyzes the process of consolidation of bipartisanship in the State as well as the way in which political alternation became      a regular situation for elections since 1983. Results show that both the Institutional Revolutionary Party [Partido Revolucionario Institucional –PRI–] and the National Action Party [Partido Acción Nacional –PAN–] have concentrated most of the votes in the elections.