the presidential election of 2006 has been the most competitive in the mexican electoral history and the explanations for this are not yet clear. making use of exit polls, this work presents a systematic analysis of the socio-economic, cultural and political preferences built around the election, as well as that of the congress. it was found that felipe calderón was more popular among young people and women, especially among the higher education and higher earnings. on the other hand, andrés manuel lópez obrador was more successful among old adults with low incomes, fighting against roberto madrazo from the vote of the poorest sectors. the results underscore the importance of the variable of presidential approval in the prediction of the vote. we would like to stress that the reviews of the economy staff do not have a statistically significant effect on the decision of the voters.