To improve our understanding of the association between income and mortality, we analysed prospective record linkage data on Finns aged 30 and over in 1997. The results show a weaker association of mortality with household disposable income—the measure that best captures consumption potential—than with individual income, particularly above age 65 when the ability to work does not bias the associations. The association between income and mortality is greatly weakened by adjustment for socio-economic status and economic activity, and there is also weak evidence of curvature in the relationship with household disposable income. Among younger participants, social characteristics of the family of origin and early career incomes have a very limited effect on the association between adult income and mortality. The causal effects of income on mortality remain difficult to establish with certainty, and may easily be overestimated. Causal explanations based solely on material factors should be treated with scepticism.