During recent years teaching practice has gained importance as a significant period of learning for the development of teacher competences. These teacher competences are regarded as the possession and development of sufficient skills, knowledge, appropriate attitudes and experience for the successful performance of one’s professional roles as a teacher (McNamara, 1992). Hence, many teacher education institutions are aiming at the development of teacher competences (also) during teaching practice. A popular instrument to achieve this aim and to assess the development of teacher competences is the electronic portfolio. This research study investigates the use and effects of a competence-based electronic portfolio procedure for the assessment of teacher competences during teaching practice in a Flemish academic teacher education program. Therefore, questionnaires and semi-structured interviews were administered by three parties, student teachers (N=41), lecturers (N=25) and mentor teachers (N=46). Results show that the portfolio proofs to be a useful instrument for the assessment of teacher competences according to lecturers and mentor teachers. Student teachers, in contrast, do not belief that the portfolio achieves this aim. In their views, the portfolio is unable to reflect and demonstrate their teacher competences sufficiently. Why that is the case, is the central focus of this presentation.