A large body of research has documented persistent social inequality in health between groups defined by race/ethnicity and socioeconomic status (SES), showing that minorities and groups of lower SES have lower life expectancy, greater risk of mortality at all ages, and earlier onset and greater severity of many chronic diseases, even after adjusting for differences in health care access and health behaviors. Scholars of the social determinants of health have argued that to advance the scientific understanding of such disparities and formulate effective responses to them requires research designed to investigate key aspects of the social environment that are linked to race/ethnicity and SES, examine how they cumulate over the life course, and link these social factors to biological processes related to health. One of the biggest social changes to have a disproportionate impact on minorities and people of lower SES in the United States in recent years has been the 705% increase in the size of the incarcerated population over the last four decades. Yet relatively little research has investigated the effects of incarceration on health and health disparities, in part because the incarcerated population is underrepresented in most data used to study health and mortality. Moreover, prior studies on the health effects of incarceration have been limited by difficulty in finding appropriate comparison groups and vulnerability to unobserved confounders that threaten causal inferences. The current project will examine the effects of incarceration the risk of mortality, using data on the population of all individuals sentenced to felonies in Michigan from 2003 to 2006 (n?130,000) and matching these individuals to death records from the National Death Index. Causal effects will rest on comparisons between convicted felons who received different types of sentences (e.g., prison time, probation) and be estimated using (a) an instrumental variables design that leverages the random assignment of felony cases to judges, and (b) a design that capitalizes on ?regression discontinuities? in the probability of being sentenced to prison based on the operation of the Michigan Sentencing Guidelines. The proposed analysis would also explore effect heterogeneity in the impact of incarceration on mortality among felony offenders across demographic subgroups and specific causes of death. The project is significant in its focus on the health effects of incarceration, a potentially large but understudied source of health disparities. It is innovative in utilizing a quasi-experimental design, allowing for stronger causal inferences on the effects of incarceration than previously possible, and compiling longitudinal data on a large statewide cohort of felony offenders, allowing for comparisons between offenders who received different types of sanctions.