Many of the leading causes of death and disability in the United States and other countries are associated with socioeconomic position. The least well-off suffer a disproportionate share of the burden of disease, including depression, obesity, and diabetes. Research suggests that the adverse effects of economic hardship on both mental and physical health and functioning are evident at young ages and persist across the lifecourse. Moreover, these associations are seen across cultures. Data from four large epidemiologic studies on the role of psychological characteristics, social factors, and behaviors in health and disease risk are presented that highlight the striking associations between socioeconomic factors and chronic diseases. Data from these studies demonstrate that the effects of economic disadvantage are cumulative, with the greatest risk of poor mental and physical health seen among those who experienced sustained hardship over time.