This article reports on a research project that studied the nature of reflection in the portfolios of student teachers: 39 learning portfolios were analysed. Current theories on reflection offered little on which to base a system of categories for analysing the content of the portfolios. Theory on learning activities was used. We found that the student teachers tended to focus in their portfolios on their own practice and how to improve it. They examined what they had done and learned, in what aspects they had made progress, and they formulated plans for the future. When looking back on their development as teachers, the students discussed individual experiences which had been important to them, as well as making connections between different experiences over a period of time. The student teachers made less use of the portfolios to gain a better understanding of situations and developments that had occurred. Supervision and guidance on the production of portfolios seemed to be essential to encourage this activity.