This study examines whether education had a causal impact on health, following synthetic cohorts using successive U.S. Censuses to estimate the impact of educational attainment on mortality rates. It focuses on compulsory education laws from 1915 to 1939, a time when at least 30 states changed their compulsory schooling and child labor laws, as instruments for education. Highlighting data from the 1960, 1970, and 1980 U.S. Census, the study looks at people who were 14 years old between 1915-39. It also uses data from the National Health and Nutrition Examination Survey I Epidemiologic Followup Study 1992. Results indicate that education had a large causal impact on mortality and that this effect is perhaps larger than had been previously estimated in the literature. This evidence of increased life expectancy related to educational attainment implies that returns to education measured only in terms of earnings increases substantially underestimates the true returns to education. An appendix presents trends for compulsory education and child labor laws. (Contains 65 references.) (SM)