O presente artigo analisa historicamente o conceito de desigualdade e aborda o tratamento dado à desigualdade em saúde. São analisadas as desigualdades naturais e sociais, o conceito de eqüidade, as explicações teóricas sobre a desigualdade e a estratificação nas sociedades modernas. Finalmente, são analisadas as relações entre os estudos sobre desigualdades sociais em saúde e a epidemiologia, desde o nascimento dessa disciplina, passando pela era bacteriológica e chegando aos dias de hoje, em que cresce o interesse pelo tema.

In this paper we present a historical analysis of the concept of inequality, and we also discuss how inequality has been viewed within the field of health. Natural and social inequalities are discussed, along with the concept of equity, theoretical explanations for inequality, and stratification in modern societies. Finally, we focus on the relationships between epidemiology and studies on social inequalities in health since epidemiology was established as a discipline, during the so-called bacteriological era, and at the present time, when there is a growing interest in social inequalities in health.