This dissertation examines the impact of a healthcare reform that aimed to provide universal access to care for a specific set of diseases in Chile. By investigating the impact of the Explicit Health Guarantees program on mortality and health care outcomes, we hope to contribute to understanding the effectiveness of alternative health reforms and their potential for improving health outcomes in Latin America and beyond. The findings are based on Chile’s complete death and inpatient records and a difference-in-differences research design. The study reveals a 4.4% decline in deaths from the diseases covered by the reform, with a more significant effect observed in diseases that are more responsive to healthcare, declining by 7.1%. The reform resulted in over 1,000 deaths averted per year. Furthermore, the reform led to a 16.3% increase in surgeries and a 6.9% decrease in in-hospital deaths related to the covered conditions. Falsification models find no significant mortality effects on these covered diseases in other Latin American countries in these same years, thus strengthening the causal interpretation of our findings. Finally, we focus on socioeconomic, demographic, and geographic patterns of the reform’s effects. The study found that public healthcare providers’ patients benefited more than private clinics, which helped narrow some of the well-known socioeconomic disparities. Although the reform targeted sex-specific diseases, the study found no significant differences in the mortality reduction by sex, but important differences between age groups. Notably, and despite the fact that the increase in surgeries is similar for those between 0 and 49 and those above 80, the proportionate decrease in deaths between ages 0 and 49 was almost four times larger than the decrease in deaths among those above 80. In addition, the study found that the reform did not significantly affect deaths in the Capital city, which had the best pre-reform access to care but decreased deaths elsewhere. Overall, the reform led to a 0.29-year increase in life expectancy.