The purpose of this thesis is studying the syndicate as a training institution for teachers, seeking to identify the contributions of union participation to teaching through interviews on the life trajectories of militant teachers, questionnaires applied to members of the basis and the union leardership in assembly and observings of the ordinary and extraordinary forums promoted by the Union of Education Professionals of Duque de Caxias (Sepe/Caxias). The choice of this nucleus was due to its 38 – year history of struggles together with the education professionals at this city. Fifteen teachers from different school levels with more than 5 years of militant unionism were interviewed together with SEPE Caxias, which reported their social origins, formation trajectory, introduction in teaching and their union experience. In these reports the poor backgrounds, weekly schooled and less politicized families stood out. The introduction to militancy occurs through networks of sociability, as a young group and participation in the basic ecclesial communities, in which the subjects are encouraged to act in the world. Universities, residents associations and political parties also take important parts as bridges to approach with the union. Through a growing work with the syndical movement, the subjects report to create new perspectives for teaching and society, contributing to the construction of a more critical teaching identity. The questionnaires highlighted the repercussions of union involvement in the relations established at school, sometimes tending towards rejection, or prestige, the militant teacher sees the professional trajectory also marked by his/her union trajectory. The aim of this study was to understand the role of teachers in their monthly meetings of school representatives, assemblies, forums, acts and other spaces promoted by the union, and to understand their role in this social context, learning the formative dimension of different spaces and times organized by that institution. At the data cross-checking, it was possible to identify two types of syndical formation. The one that happens on the daily routine of actions among peers and the one that is previously organized aiming at a specific goal. The first is a political-syndical formation that happens through participation in the meetings, councils, assemblies, acts and other actions promoted by the union. It is linked to knowledge of rights, interaction with society and awareness as a teaching category. Although it is aimed at collective action, this type of training is difficult to measure, since it acts upon knowledge and personal experiences of each participant. Therefore, their leaning varies according to their previous provisions and intensity of action on the union movement. The second type is a political-pedagogical formation. It follows a specific goal, oftentimes pedagogical or functional. It aims to meet a demand imposed on the union connected to the struggle for improvement of teaching conditions. For its execution interchange among institutions was resorted, seeking the help of academic experts. On the other hand, professional experience, both academic and acquired in different areas of militancy, was also used. In conclusion, we point out the importance of the unions in the training of teachers, especially in times of democratic instability in which the precariousness of regency is accentuated; as well as projects of withdrawal of rights and loss of teacher autonomy tend to be more frequent.