Statistical evidence suggests that social cohesion provides the link between income inequality and health, but it is not clear how it might do so. The vagueness of the concept of cohesion and the difficulty of seeing how something so apparently ephemeral could exert a major influence on health has led to skepticism about its role in the relation between income distribution and mortality. The author suggests that social cohesion is indicative of underlying psychosocial risk factors that are known to be closely associated with health. Attention is drawn to the strong inverse relationships between measures of social inequality and measures of the quality of social relations in numerous different data sets. Given that social status and social affiliations, in terms of population-attributable risks, are among the most powerful influences on population health in the developed world, this is a potentially potent mixture for health. An antipathy between hierarchical relations across inequalities of power, income, and status on the one hand, and supportive social relations between equals on the other, is likely to exert a powerful influence on health.