Relating to the teacher´s work professionalisation, the need for searching for new ways arises in order to answer the question of how to improve teacher´s subject didactical competence. The study tries to: a) show the role of qualified pedagogical reflection in this process; b) characterize some aspects that enable us to register and evaluate changes that arose in the process. Firstly we deal with our perception of competences. Secondly we give a more detailed description on our perception of joint reflection and their significance. Next we show how we- using comparison of the reflections and clasroom observation - judge the development of one particular teacher, who has been cooperating with us on a long term basis.