The persistent economic development gap among countries in Latin America has led to structural conditions that explain, at least in part, the continuing inflow of regional migrants to countries such as Argentina, Chile and Costa Rica. However, the insertion of regional migrants in these labour markets is significantly more precarious than that of the natives, a situation that is expressed through a very high percentage of workers not covered by social security system, unprotected by human rights and obtaining very low wages. The informality of these jobs also implies the lack of access to health care and pension benefits when they retire, with a negative impact on the social vulnerability of these workers and their families. Also, in times of crisis, migrant workers are the first to lose jobs. On top of that, they do not have social protection mechanisms to mitigate the impacts on their family income. The aim of this study is to analyse in depth the working conditions of regional migrants living in Argentina, Chile and Costa Rica –which are among the most important receiving countries in Latin America-, compared to the insertion of native workers in these labour markets. The degree of informality, job segregation and income discrimination will be especially studied from a comparative perspective among these countries