In emerging economies, the socio-economic status is a key element to evaluate social improvement as it provides an understanding of the population's access to housing, education, health or basic services like water and electricity. The relationship between such indicators and human physical mobility has been researched mostly in areas like access to medical infrastructures and public transportation. However, such studies have been limited in scope mostly due to the lack of large scale human mobility information. Nevertheless, the recent adoption of cell phones by large social groups in emerging economies has made it possible to capture large scale data about human physical mobility, which combined with regional socio-economic levels, allows to study the relationship between socio-economic indices and human mobility. In this paper we study the relationship between mobility variables and socio-economic levels using cell phone traces. Our results indicate that populations with higher socio-economic levels are strongly linked to larger mobility ranges than populations from lower socio-economic status. Finally, we also present a model that formalizes our findings on the relation between socio-economic levels and human mobility.