Because of the paucity of data on the geographical distribution of mortality and deprivation in the Republic of Ireland, we calculated SMRs for each county for the years 1982-6. Two measures of mortality were used, all cause and avoidable mortality. Two indexes of deprivation were also calculated for each county, Townsend's and a new Irish index. Significant differences in mortality exist between counties. Counties that had SMRs significantly below the national standard of 100 were Meath, Donegal and Galway. Counties with significantly high SMRs were Louth, Limerick and Westmeath. County SMRs were correlated with both deprivation indexes and no significant correlation was found to explain the apparent differences in mortality.