This paper examines impacts of childhood health on SES outcomes observed during adulthoodlevels and trajectories of education, family income, household wealth, individual earnings and labor supply. The analysis is conducted using data that collects these SES measures in a panel who were originally children and who are now well into their adult years. Since all siblings are in the panel, one can control for unmeasured family and neighborhood background effects. With the exception of education, poor childhood health has a quantitatively large effect on all these outcomes. Moreover, these estimated effects are larger when unobserved family effects are controlled. (JEL codes; I 10 , J 00 )There is renewed scholarly and policy interest in why adults of lower socio-economic status (SES) have worse health outcomes. No matter which measures of SES are used (income, wealth, or education), the evidence that this association is large is abundant (Marmot, 1999;Smith, 1999). A key issue concerns the extent to which childhood health status affects levels and trajectories of the most central measures of SES including education, income, and wealth during one's adult years. But estimating this relationship is difficult, as it requires data that follow individuals from their childhood years into a significant part of their adulthood, all the while simultaneously measuring health and these key SES concepts. Since unmeasured attributes of the family, neighborhood and environment in which people are raised may be determinants of their adult outcomes and trajectories, data must permit some control for them, especially that undoubtedly large sub-component that is unmeasured in most surveys. This paper uses unique data derived from the Panel Survey of Income Dynamics (PSID) that has followed groups of siblings and their parents for as long as 30 years. Throughout that period, information on education, income, wealth, and health were collected prospectively on all parties. Following siblings from the same family offers an excellent opportunity to control for unmeasured family and other background effects common to children raised in the same family especially in light of the detailed and long histories of economic status available for these children when they are adults in the PSID. Using this data, I present estimates that indicate that health conditions during childhood have quantitatively large impacts on virtually all key adult indicators of socioeconomic status used by economists. This paper is divided into three sections. The first briefly summarizes some recent contributions by economists on the question of the origins and impact of childhood health on adult outcomes. Section 2 highlights the salient strengths and weaknesses of the data that will be used in the analysis. The final section contains empirical models that investigate the * Smith is a Senior Economist at RAND and holds the RAND chair in Labor Market and Demographic Studies. The programming assistance of David Rumpel is gratefully appreciated. This paper benef...