ABSTRACT Introduction: In Brazil, there is a considerable number of deaf people, sign language users, who should have access to equal opportunities. However, sign language is unknown by the most Brazilian population, especially those who work in public institutions, and deny the deaf their rights to equality. Therefore, several professionals, among them, the municipal guards, are not prepared for the diversity. Purpose: to investigate the knowledge of the Municipal Guards (MG) from Curitiba about the deaf, Brazilian Sign Language (Libras),and their service practices when they need to interact with deaf citizens. Method: It´s a mixed crosscut study; data were collected by the application of a semi-structured questionnaire answered by 50 municipal guards, with questions on their knowledge about the deaf, the sign language and the service practices conducted by their corporation towards deaf people. Data were analyzed quantitatively and qualitatively by means of Bardin’s Content Analysis. Results: The results demonstrate that participants have a limited knowledge of deafness and Libras. Conclusion: Most members of the Municipal Guard have a view of deaf people and the Brazilian Sign Language based on an organic perspective of deafness, and it was also observed that during their service practices towards deaf people, many of them could not either interact or communicate with them.