The non-existance of a clear borderline between the social and the public health researches through the application of social sciences methodology, is commented. After this, work intends: 1) to form an opinion about social research in public health showing its difference from social research; 2) to show, in a systematic maner, the main social investigation trends in public health; 3) to establish the area of competence of the public health worker related to social research in public health.