PROGRESA is one of the Mexican government's major programs aimed at developing the human capital of poor households. In early 1998, IFPRI was asked to assist Mexico's government to determine if PROGRESA was functioning as it was intended to. This research report synthesizes IFPRI's findings about PROGRESA's impact and operation. The majority of IFPRI's findings suggest that PROGRESA's combination of education, health, and nutrition interventions into one integrated package has had a significant positive impact on the welfare and human capital of poor rural families. The report will interest researchers, policymakers, and advisers seeking a better sense of the basic elements of a program that can be effective in alleviating poverty in the short and long run.