Population censuses in Latin America have generally recorded the place of birth of all persons enumerated. The use of those data for the study of international migration has been less common because international movements were judged to be a relatively weak factor determining demographic change in the majority of Latin American countries and because the data gathered were generally not tabulated with sufficient detail. During the 1970s, the UN Latin American Demographic Center (CELADE) realized that international migration was not necessarily a minor factor in their evolution and launched a program to improve the quality and availability of census information on the foreign-born population enumerated by each country. The program on International Migration in Latin America (IMILA) has therefore been in operation for more than 10 years and has been successful in eliciting the in-depth tabulation and exploitation of census information in the majority of Latin American countries and in the 2 main receivers in the Americas: Canada and the US. As part of the IMILA project, CELADE has become the depository of magnetic tapes with census information on the foreign-born population, thus gaining greater flexibility in the exploitation of the data available. On the basis of the information gathered, CELADE has published twice in the past decade a compilation of tabulations of the foreign-born population by country of enumeration, country of birth, age, and sex. Although census data on place of birth are not free from problems, particularly in countries where illegal migrants may not be adequately enumerated by a census, they are a valuable source of reasonably comparable information on the overall impact of migration in receiving countries and are often the only source of information on emigration from the sending countries.