The purpose of this study was to examine engineering university professors' teaching identity formation as a result of their experiences derived from their teaching practices. We used the position of cultural psychology and conception of identity in the practice of Wenger (2001). The stories of ten engineering professors from a Mexican university were retrieved through open-ended qualitative interviews. The results showed that the main coincidence in the process of being and identifying as a teacher was the interest in students and learning. We concluded the teacher identity construction developed through experiences of successful teaching practices and the commitment towards student training.