There is abundant evidence of a relationship between socio-economic variables, such as income, wealth or labour position, and a variety of health outcomes, in terms of mortality and morbidity. Recently, some scientists have tried to prove that is not income itself, but inequality in income, that causes negative effects on health. This kind of approach is named relative income hypothesis, in contrast to the absolute income hypothesis. Another approach, held mostly by academic economists, denies
the existence of a causal link between income and health, and supports the opposite causality relationship, which considers the initial stock of health as the determining factor of individual income and wealth. The first part of the paper provides an overview of the existing literature on the connection between socio-economic variables and health in industrialized countries. The second part is devoted to comment on the existing debate between the absolute income and relative income assumptions, and on the analysis of the different health policy measures that each approach implies.