Introduction To assess health inequalities is an important issue in a country like Brazil with one of the highest income inequities in the world. The aim of this study was to analyse the magnitude of social inequalities in mortality among population aged 20 and older, living in a city of one million people in Southeastern Brazil, in 2004–2008.

Methods The 49 areas of healthcare units were classified into 3 homogeneous strata using 2000 Census small-area socioeconomic indicators. Mortality rates by age group, cause of death (ICD10 codes) and sex were calculated for each stratum. Rates ratio (RR) and 95% CIs were estimated for low and middle stratum in relation to the highest.

Results In general, age-group-specific rates had a social gradient with declining risks of death from higher to lower stratum. In overall mortality, inequalities among strata were statistically significant. Inequalities between Low and High stratum were higher among females, except for external causes of injury. The greatest differences among males were recorded for homicides (RR=2.4), traffic accidents (RR=1.6) and cerebrovascular diseases (RR=1.6). Among women, cerebrovascular and chronic lower respiratory diseases showed the greatest inequalities, both with risk of death 2.2 times higher in the lower stratum. Only breast cancer had a reversed social gradient.

Conclusion Since unfavourable living conditions are related to unhealthy behaviours and to difficulties in access to health services, to reduce the health disparities, the National Health System should assure greater access to health services and promotion of healthier lifestyle among vulnerable groups.