Background: The study of mortality differentials by class or socio-economic group is underdeveloped in Ireland in comparison to other countries. The work that has been done has used a standardized mortality ratio (SMR) methodology to measure deaths. There has been no previous work exploring the social gradient in years of potential life lost (YPLL) in Ireland. Methods: The aim is to investigate socio-economic mortality differentials for men aged between 15 and 69 in Ireland, using VILL as a measure of premature mortality. The design is a mortality trends study. The study is based on mortality data supplied by the Central Statistics Office in Ireland and population data taken from the Census for the years 1981 and 1991. The data covers all male deaths aged 15-69 in the years 1981 and 1991. Social position is measured by a 12-category socio-economic group (SEG) framework and by a more aggregate four-category occupational classification system. Result!;: When age at death is taken into account through YPLL, injury and poisoning is a major cause of premature mortality in Ireland for all soclo-economic groups. The results also show significant differentials in VILL by 12-category SEG in Ireland. There was a widening of the social gap during the period 1981 to 1991 as measured by the VILL ratio between lower manual/upper non-manual occupational groups. The use of YPLL as a measure of premature mortality highlights the importance of respiratory disease and injury and poisoning as the major sources of health Inequality in 1981 and 1991. Conclusions: VILL is an. important indicator of general mortality and for monitoring mortality differentials by socio-economic group. Current health inequalities as measured by VILL are unacceptably high in Ireland. A comprehensive government strategy to reduce inequalities in mortality is required, having the primary objective of improving the economic and social circumstances of people in the lower manual occupational category. There is also a need to develop measurable priorities and programmes for the reduction of premature mortality in the injury and poisoning category for all social groups, and especially for people in the lower manual group. This means action now to prevent future deaths from road accidents, accidents at work and suicides.