This study is developed around the concept of teachers professionality understood as a set of behaviors, knowledge, skills, attitudes and values that constitute the specificity of being a teacher. In this sense, are subscribed in the teachers professionality the construction of professional identity and specific knowledge of teaching. So, interested in understanding how the teachers practice their professionality in the school and if they have some kind of autonomy in work organization within the school, the purpose of this research was to understand the ways how teachers live the teaching profession and how they face the challenges of everyday into the environment of a school unit pertaining to a large network of private schools. The study is part of the research The teacher work in private schools for popular sectors: a forgotten object being conducted by GEPPE (Group of Studies and Research on Teacher and Teaching), coordinated by Professor Isabel Lelis in the Department of Education of the Pontifical Catholic University of Rio de Janeiro (PUC-Rio), was conducted through semi-structured interviews with 10 teachers of the early years of elementary school in a philanthropic school unit, located in a slum in Rio de Janeiro, belonging to a large network of private schools. A network of private schools studied is composed of 27 school units and has some peculiarities in their organization, localization and pedagogical management justifying the interest of study, such as standardized teaching material purchased from a education system, designs purchased from another education system, standardized tests for the whole network and the use of manuals for instrumentation of teachers work. Thus, seeking to achieve the objective set, the analysis of the data produced is delineated from the teacher work. Approach issues related to the use of specific teaching knowledge, challenges of professional practice in everyday school, practice of teaching autonomy, factors (de) motivation and (dis) investment of teachers with the profession a their relationship among the pairs revealing the different ways teachers develop and live the professionality. All dates show for the construction of very different professional cultures within the school that may be at the core of a new model (if not unrealized, desired by large school systems) of teacher professionalization. The teachers interviews revealed different ways of dealing with the professionality before the adversity and pressure of the network characteristics of the organizational model of this kind of school, reflecting negatively on the development and affirmation of teacher professionality. Indeed, the study found that the circumstances of the work environment have implications for the development of teacher professionality resulting in feelings varied in the teachers which ranging from the motivation up to the technical realization of teacher work which usually cause the isolation of teachers hindering the construction of a professional culture more colaborative.