This article reports on a study of pre-service French immersion teachers who were required to compile second language (L2) portfolios as part of their professional development. Documents included a brief biography of the students' lives as speakers and learners of French; an action plan in which students assessed their L2 proficiency and set specific language learning goals; artefacts from both in-class and out-of-class learning experiences; and a final narrative entry commenting on the degree of success of their action plan. Volunteers participated in semi-structured audiotaped interviews and allowed their portfolios to be copied. Although the project was not as successful as initially anticipated, the process of compiling portfolios created a new space for L2 development. The portfolio became a tool mediating language learning activities. Furthermore, students showed that they were less capable of working autonomously than had been anticipated and that they required encouragement and support throughout the project.