Portfolio assessment practices are expanding and showing substantial diversification. After a short review of these developments, we present an approach which was experimented in two elementary school classes (fourth and sixth grades). This approach was designed, first of all, to enhance the formative and metacognitive dimensions of students' implication in the preparation of their portfolios. Secondly, it places the portfolio in the dynamic context of a three-way conference involving the teacher, the student and the student's parents. The study was based on a sample of 10 students (and their parents) per class. The data collected in the classroom and during the conferences demonstrated several advantages of this assessment approach: active implication and responsibility on the part of the student, in-depth exchanges between family and school, enhancing of student perspectives and projects. Difficulties were observed, however, in some cases, particularly when there was a sizeable distance between family and school cultures or when relational problems emerged during the conference.