Transitions in teaching identity: changes in the curriculum and critical incidents in teachers of portuguese as a foreign language Summary The following text shows a qualitative research about the different scenarios experienced by Foreign Language teachers during a process of curriculum change, as well as their didactic approaches originated from the implementation of a new model in their institution. Adiscursive device called Critical Incident (IC in spanish) was used to carry the aforementioned analysis. IC are those events found in the daily practice (extracted from own experience) that impact, destablize or surprise (because of its good or bad course) to a specific individual as well as motivate or trigger a deep reflection upon it. To approach such complications, we chose the specific case of the Portuguese Department at the Foreign Language Institute (CELE in spanish) at UNAM, were a nonrandom sample was taken. Such participants reobtained their ICs after getting a Guideline for the Analysis of Critical Incidents (PANIC in spanish), semi-structured interviews and digital format scripts, to be presented through the production of a Digital Personal Storytelling (RDP in spanish). From this collection tools, different methodological strategies were used to identify and analyse the paths and representations of Portuguese teachers in a context of curricular change as well as the most recurring reported ICs. Following such methodological work, a unit and sub unit research was carried out as means to identify the problematics described by the participants to find reasoned solutions to the situations reported by the teachers in a wayanalysis allowed them to learn from conflicts as well as to offer tools for management in the classroom. The cited before, allowed them to reflect upon the path, practice and profesional identity of the Teacher of a Foreign Language as well as to consider alternatives for the identified ICs from contextual defined dynamics. Oportunities were shown to reflect and to transform the pedagogical praxis, as well as to open a new way for the teaching training heading to an improvement and evaluation for the control of the affective, emotional and relational aspects produced in those destabilizing situations. Keywords: teaching practice, curriculum change, language teaching, critical incidents.