The official figures which appear to show a widening of class differences in health in England and Wales during the post-war period have been controversial partly because they do not fit with common perceptions of what has happened to differences in the standard of living. As a result, a great deal of effort has gone into investigating suggested weaknesses in the decennial social class mortality data. Though initially plausible, the artifactual and selective explanations of the widening mortality differences which were put forward have not usually been borne out by closer investigations. The only fault in the broad picture presented by the official data which we do perhaps need to bear in mind is the tendency for a narrowing of mortality differentials among younger women to be masked by the widening among older women. This paper is an attempt to look at the other side of the coin—namely, to investigate trends in differences in the standard of living in relation to mortality differentials. It concludes that trends in mortality differences have not been related to trends in class differences in average earnings, but have been fairly clearly related to trends in relative poverty. Relative poverty and class differences in mortality declined before the war but have both increased, decade by decade, since the war. Younger women have perhaps been protected from the increase in relative poverty during much of the post-war period by their increased economic activity rates and the relative improvement in earnings of women in poorly paid manual occupations.