This study investigates the relationship between health care expenditures and mortality in developing countries. In addition, the difference in impact of public and private expenditures is investigated. This study uses country level aggregated data from developing countries, as defined by the World Bank’s 2021 income classification system, over a 15-year period from 2003 to 2018. The results indicate that total health care expenditures per capita have a significant negative correlation with infant mortality but a significant positive correlation with adult mortality. In all populations, higher percentages of out-of-pocket expenditures increased mortality rates, while higher levels of public expenditures showed a significant negative correlation with mortality rates. Additionally, higher levels of private expenditures consistently showed a positive correlation with mortality rates.