As Mexico experiences rapid population aging, the Mexican Health and Aging Study (MHAS) provides nationally representative longitudinal data that help researchers understand the health, economic, and social circumstances of adults age 50 and older. Through the Gateway Harmonized MHAS, these data can also be compared across the international family of Health and Retirement studies, contributing to the cross-national evidence highlighted in the U.S. Census Bureau’s An Aging World: 2025 report.