The article shows how in 1840's, following the proposal of colonization projects that contemplated the immigration of foreigners, religious tolerance was debated in Mexico and "Nueva Granada".We argue that these proposals for colonization showed clearly the relationship between religious tolerance and immigration.This means that the religious tolerance was a fundamental condition for the immigration, in which, religious tolerance acquired a practical connotation.We describe, analyze and interpret the arguments, for and against, representations and imaginaries, that were built on the relationship between religious tolerance and immigration.The discussions on religious tolerance related to immigration are immersed in broader debates.In these debates, politics and religion played an important role in creating ways of seeing and living the world.