This paper aims to address the relationship between professional ethics, deontology and union organization in Brazilian Librarianship, intending to understand how the process of political-institutional interaction of the area is situated in the professional and educational context. The methodology uses data collection, bibliographical and documental research. It presents concepts related to ethics as a science and its importance in the field of professions. It relates ethics and deontology, understanding this as a science of duty, responsible for ascertaining how the norms guiding the professional classes arise and are sustained. It evokes historical elements of the trade union movement in England, its arrival in Brazil and the beginning of unionization of Brazilian librarians. As a result, it highlights the need to broaden the debates about professional ethics and the maturation of class consciousness in Librarianship, which may have repercussions on collective actions of greater visibility with society.