The historical conditions surrounding the emergence, by the mid-19th century, of epidemiology as a scientific discipline, were analysed. Special consideration is given to the influence of the political milieu of Victorian England in the definition of the theoretical basis of epidemiology. The English Sanitary Movement is seen as a response of the emerging bourgeoise to problems created by industrialization and urbanization. As a consequence, epidemiology was strongly influenced by Stuart Mill's system of logic. During the latter part of the 19th century, bacteriology brought important transformations to epidemiology. However, its theoretical foundations suffered almost no change. Possibly the new challenges created by -the expanding colonial empires were the driving force in the evolution of epidemiology. As a science, it could not escape from the influence of social and political forces, It has only been recently, mainly in Latin America, that a search for alternatives to the dominating theoretical structure of epidemiology has taken place. The historical-materialist approach has given way to what is sometimes refered to as social epidemiology. Epidemiology should be regarded as a science in which different theoretical approaches may coexist, as in history, sociology or physics.São analisadas as condições históricas do surgimento da epidemiologia como disciplina científica, em meados do século passado. É revista a evolução das bases teóricas do processo explicativo em epidemiologia até o momento atual. Especial atenção é dada ao papel da lógica positivista de Stuart Mill como base teórica da Epidemiologia até recentemente. São discutidas as alternativas teóricas correntes e proposta maior abertura da epidemiologia a diferentes correntes filosóficas como o caminho para o estabelecimento da epidemiologia como uma ciência madura.377383