We examine the relationship between income and health with the purpose of establishing the extent to which the distribution of health in a population contributes to income inequality and is itself a product of that inequality. The evidence supports a substantial impact of ill-health on income, mainly operating through employment, although the magnitude of ill-health's contribution to income inequality is difficult to gauge. Variation in exposure to health risks early in life could be an important mechanism through which health may generate and possibly sustain economic inequality. If material advantage can be exercised within the domain of health, then economic inequality will generate health inequality. In high-income countries, the evidence that income (wealth) does have a causal impact on health in adulthood is weak. But this may simply reflect the difficulty of identifying a relationship that, should it exist, is likely to emerge over a lifetime as poor material living conditions slowly take their toll on health. There is little credible evidence to support the claim that the economic inequality in society threatens the health of all its members or that relative income is a determinant of health.