A vast archive of raw census microdata covering Latin America in the period since 1960 survives in machine- readable form. Over the past five years, this project has made a substantial portion of these data available to researchers for the first time. This proposal seeks funding to complete work on an integrated database including samples of approximately 100 Latin American and Caribbean censuses. These microdata and accompanying documentation will be made available for scholarly and educational research through a web- based data dissemination system. This project leverages previous federal investments in social science infrastructure. Grants from the National Institutes of Health and the National Science Foundation laid the groundwork for the Latin American data series by funding many of the initial costs. Those projects underwrote the development of data cleaning and sampling procedures, metadata systems, data conversion and dissemination software, and design protocols for data and documentation. Raw microdata files, internal documentation, and redistribution agreements for the censuses of virtually every Latin American country have been obtained. As a result, this project is highly cost- effective. The project has four major goals: 1) expand the database dramatically, doubling the number of countries included and adding the 2010 round of censuses for each country, increasing the total size of the database by some 92%;2) improve variable coding, especially for geographic variables;3) create and disseminate new data products, including geographic boundary files, aggregate summary files that are consistent across time and space, and restricted access microdata that include complete enumerations with full geographic codes; and, 4) implement new infrastructure to improve data access and user support and reduce the cost of long- term maintenance. With 150 million records of public-access data and over a half-billion records of restricted-access data spanning a fifty-year period, the new database will allow social scientists to make comparisons across Latin American nations during a period of transformative change. It will be a powerful resource for understanding the causes and consequences of the extraordinary social and economic transformations that have reshaped the hemisphere during the past half century, including new scientific and policy-relevant health-related research on economic development, demographic transition and population aging, and international migration. Project Narrative The proposed database is directly relevant to the central mission of the National Institutes of Health as the steward of medical and behavioral research for the nation;this infrastructure will advance fundamental knowledge about the nature of human population dynamics and will spark new health-related research. The data series will result in a substantial body of new scientific and policy-relevant health-related research on economic development, demographic transition, population aging, and international migration. By opening access to a vast collection of microdata, the project will allow social science and health researchers to address fundamental questions about the impact of the extraordinary social and economic transformations that have reshaped the hemisphere during the past half century.