This study makes the first systematic attempt to trace the long-term development of Latin American numeracy, a phenomenon of great interest to economic historians in that it serves as an accurate gauge of human capital development. In order to approximate basic numeracy we use age-heaping techniques. We find that Latin America was on a path of convergence with western Europe during the early eighteenth century. During the early nineteenth century, not only did numeracy development stagnate in some Latin American countries but differences among some of them actually increased. While numeracy rates in Argentina, Uruguay, and to a lesser extent Brazil, along with Europe, underwent a significant increase in the late nineteenth century, they declined in Mexico, Ecuador, and Colombia. By performing a regression analysis, we find that, even when we control for investment in education, mass immigration contributed to human capital formation.