This paper measures inequality of opportunity in adult health in Colombia employing the 2010 Living Standards and Social Mobility Survey. I study the relationship between childhood circumstances and health status in adulthood drawing on Roemer (1998)'s analytical approach to inequality of opportunity. I use stochastic dominance tests to capture differences in the conditional distributions of self-assessed health. This test is an initial assessment of inequality emerging from early life circumstances like parental education, household socioeconomic status in childhood and parental survival. I also calculate a dissimilarity index to provide a measure of inequality of opportunity in health and obtain the relative contributions of various circumstances using logistic regressions and the Shapley value decomposition. Since a limited set of circumstances are observed in the data, my estimation of inequality of opportunity provides a lower bound on the true inequality of opportunity. The findings suggest that there is substantial inequality of opportunity in adult health. Moreover, differences in household socioeconomic status during childhood and parental educational attainment appear to be the most important dimensions of inequality of opportunity in adult health.