The usage of portfolio methods to document professional development in teaching is increasing in Germany, but despite its proliferation, the issue of how the effects of portfolio methods can be determined has received little attention. In this two-part study, the attitudes of both pre-service teachers and teacher educators toward portfolio are investigated and an attempt is made to identify the effects of portfolio on the competences and attitudes of the pre-service teachers. Results suggest that the efficiency of the portfolio method depends both on personal competences and on the framing within the training program.