ABSTRACT Poverty long has been recognized as an important social determinant of health. Despite many years of progress, in 2018 nearly 10% of the world's population lived in extreme poverty — below $1.90 per day. The Covid-19 pandemic has further increased poverty, leading to a 12% increase in extreme poverty in 2020, with ongoing increases in low-income countries in 2021. Large-scale, government-led cash transfer programs that provide money to individuals or households (with or without conditions) have been a vital part of poverty reduction strategies in many countries during the past two decades. Unlike multi-country evaluations of major health aid programs like PEPFAR, the vast majority of studies of cash transfer programs have focused on individual countries and impacts on beneficiaries in those countries, generally using datasets that are not large enough to precisely estimate effects on mortality rates and many other important health outcomes. In recent work, we used data from 37 low- and middle-income countries (LMICs) and numerous Demographic and Health Survey (DHS) surveys to generate longitudinal mortality datasets for about 7 million adults and children. Using a difference-in- differences approach, we found that government-led cash transfer programs resulted in large and statistically significant reductions in mortality among adult females (adjusted risk ratio 0.80) and children <5 years of age (adjusted risk ratio 0.90), but not among adult males or older children. This work raises an important question about the possible pathways that explain these findings, including behavioral pathways (such as increased engagement in health-promoting behaviors like antenatal care or childhood vaccination) as well as health and nutrition pathways (such as improved child nutrition). The proposed project will address this question by combining DHS data with our newly constructed database of cash transfer programs, using difference-in- differences analyses to examine the association between cash transfer programs and outcomes among adult females and children <5 years of age. Aim 1 of the project will assess the association between cash transfer programs and key behavioral outcomes that might affect mortality rates and other health outcomes, and Aim 2 will assess the associations between these programs and key health and nutrition outcomes that are of considerable interest themselves and might also mediate effects of cash programs on mortality rates. Regression models will include country and year fixed effects and time-varying confounders at the individual- and country- levels. We will conduct secondary and sensitivity analyses like temporal analyses and alternative modeling approaches to assess the robustness of our results, including use of alternative estimators to address bias that can be introduced in difference-in-differences analyses with variation in intervention timing. At a time when many countries are considering scaling-back or expanding c...