This paper presents two different yet complementary on-going studies related to the understanding of the mechanisms leading to social inequalities in health. The first part is devoted to a differential morbidity survey held in southern Belgium. It confirms that striking differences exist in the period around birth between social categories, and between the three districts under study. In a multivariate approach, differences remain between the social categories and between the district samples, which classically studied socio-demographical, behavioural and medical characteristics cannot fully explain. The role of cultural factors is analysed and discussed through the concept of 'health culture' and alternative hypotheses are reviewed in the light of the results. The second part reviews the studies conducted on the so-called avoidable mortality in the EEC and more specifically in Belgium. The concept of avoidable mortality is discussed, as well as its utility from the standpoint of the present concern on social inequalities. Differences between EEC countries are large, and even within Belgium there are important disparities between the districts. The role of health care supply has not been demonstrated yet in these two contexts. For Belgium, it appears that a major part of the unequally distributed mortality is constituted by causes of death considered as avoidable. Moreover, the most discriminating causes of death are overrepresented in socially deprived districts. The two perspectives are confronted in order to delineate perspectives for future research and operational outcomes for policy making and interventions. © 1990. ; SCOPUS: ar.j ; info:eu-repo/semantics/published