Objetives: To describe and analyze the contributions of Supervised Training for the training of professional nursing identity.Methodology: Qualitative, descriptive study.Were interviewed eleven nursing trainees from the eighth and ninth periods and ten stage tutors of two institutions of higher education, using as research scenario their respective teaching hospitals. Interviews were consolidated in the light of the analysis of its contents.Results: Why we are and how we are constituted nurses were issues that emerged during the research directing us to study the process of identity construction by nursing intern. Associations between being an idealized nurse and the reality experienced in the workplace point and help to understand the construction of the identity of the professional.Coclusions: In nursing professional identity is formed within a collective work environment, relationships with partners (interdisciplinary team, patient and family) inserted in work situations, marked by a hierarchical division of labor and life paths, marked by unforeseen, continuities and ruptures, successes and failures. In front of the trainee, the preceptor nurse opens the curtains of knowledge and profession, showing the daily life of nurses. This workspace helps the trainees to define yourself as a person and as a professional, contributing to the construction of professional identity