The present article summarizes two years of work with the portfolio during continuing training for vocational teachers in secondary education. lt deals with the interaction between a formative and summative use of this assessment tool. The different analyses demonstrate the integrative value of the portfolio which enables differenciation of the learners' project. The proposed procedure provides moments for regulation of the learning process and therefore also determines the teaching approach. A factorial analysis of the productions regarding the portfolio completes this case study. lt examines how learners reacted to the process, as well as it highlights the themes which determine the students' underlying representations.