Every ten years, information from the decennial census is used together with national death registration data to study socio-economic differences in mortality. This article reports the findings of one of the analyses prepared for the latest decennial supplement. This volume is due for publication late in 1997. Over 175,000 deaths of men aged 20-64 in England and Wales were analysed using the Registrar General's Social Class (based on occupation) schema. The social gradient in all-cause mortality observed in earlier decades is still seen in 1991-93. In absolute terms, there has been a fall in mortality rates in England and Wales over the twenty-year period 1970-72 to 1991-93. This is reflected in the falls in mortality rates for each of the social classes I to IV over the two decades. In contrast, the mortality rate of Social Class V rose in the early 1980s. Since then, it has fallen. However, it is still higher than in the early 1970s. Trends in mortality show a relative widening of social differentials developing over this period. This is true for all-cause mortality and for the specific causes investigated in this article. Mortality is almost three times higher in Social Class V (SMR 189) than in Social Class I (SMR 66). Classes IIIM and IV (SMRs 117, 116 respectively) have nearly double the mortality of Class I. Even larger differentials are observed for stroke, lung cancer and suicide.