Objectives During the past decades a widening of the relative gap in death rates between upper and lower socioeconomic groups has been reported for several European countries. Although differential mortality decline for cardiovascular diseases has been suggested as an important contributory factor, it is not known what its quantitative contribution was, and to what extent other causes of death have contributed to the widening gap in total mortality.Methods We collected data on mortality by educational level and occupational class among men and women from national longitudinal studies in Finland, Sweden, Norway, Denmark, England/Wales, and Italy (Turin), and analysed age-standardized death rates in two recent time periods (1981-1985 and 1991-1995), both total mortality and by cause of death. For simplicity, we report on inequalities in mortality between two broad socioeconomic groups (high and low educational level, non-manual and manual occupations).Results Relative inequalities in total mortality have increased in all six countries, but absolute differences in total mortality were fairly stable, with the exception of Finland where an increase occurred. In most countries, mortality from cardiovascular diseases declined proportionally faster in the upper socioeconomic groups. The exception is Italy (Turin) where the reverse occurred. In all countries with the exception of Italy (Turin), changes in cardiovascular disease mortality contributed about half of the widening relative gap for total mortality. Other causes also made important contributions to the widening gap in total mortality. For these causes, widening inequalities were sometimes due to increasing mortality rates in the lower socioeconomic groups. We found rising rates of mortality from lung cancer, breast cancer, respiratory disease, gastrointestinal disease, and injuries among men and/or women in lower socioeconomic groups in several countries.Conclusions Reducing socioeconomic inequalities in mortality in Western Europe critically depends upon speeding up mortality declines from cardiovascular diseases in lower socioeconomic groups, and countering mortality increases from several other causes of death in lower socioeconomic groups.