The Directly Observed Treatment (DOT) is considered a milestone for TB control worldwide, which can contribute to achieving the global goals for disease control. The Ministry of Health (BRASIL, 2011b) highlights that the nurses' role is essential to ensure the supervision of the entire DOT. However, based on empirical observations of the practice and discussions in a research group between care nurses and researchers, we observed some limitations to the operationalization of the strategy regarding the nurses' performance in the OST, especially the importance given to the supervision of drug taking at the expense of other actions that are also part of the OST. The object of study of this research is the social representations about the OST for ESF nurses, using Serge Moscovici's Theory of Social Representations as a theoretical reference. This research aims to know the social representations of nurses of the Family Health Strategy (FHS) about the Directly Observed Treatment (DOT) of tuberculosis. This is a qualitative representational study, conducted in family health units that operated the DOT.