The principal aim of the project was to investigate health disparities among the elderly and old population by socioeconomic status, race and ethnicity in Mexico and the United States, and to propose potential explanations for the observed differences in morbidity and mortality observed among various population groups in the two countries. The project aimed also to investigate how the effects of socioeconomic factors such as education, race, ethnicity, sex change over the life span of individuals, and whether these effects a different among the two countries.