This article presents the results of a Master´s Program research of the Post-graduation Program in Teaching, Philosophy and History of Sciences at the UFBA/UEFS developed with primary school teachers enrolled on the Special Teaching Program (PROLE) in Chemistry at the UFBA. The History of Life method was utilized to collect and analyse the data, mainly from the theoretical contributions of Josso (2004), Nóvoa (1988, 1992 3 1995), Larrosa (1994 e 2002) e Pineau (1999), concerning the formation, self-formation and trajectory of the personal and professional development of the teachers. Despite not having a degree in Chemistry, these teachers have a great deal of experience in teaching this subject. Specially from Larrosa and Josso, the concepts of experience and forming experience were utilized, showing their relevance to the development and construction of the teachers´ professional identity. The research was carried out with 3 students of the above-mentioned program, aiming at the reconstruction of relevant bibliographical aspects that indicate the existence of those forming experiences as well their role in the teachers´ personal and professional development. The main instrument of the research was the deep interview. For the objectives of the present article, we have chosen the presentation and discussion of Marina´s history, who has been a Chemistry teacher for 24 years and has developed her method of work from her former teachers ´experiences and catechism lessons at the church she attends. The reconstruction and analysis of Marina´s life history have provided us with a better understanding of some aspects related to formation, as the influence of personal and professional daily events on the teacher´s development.