This study focused on the relationships between experiences with portfolio assessment, students' approaches to learning and their assessment preferences by means of a pre- and post-test design in an authentic class setting. The participants were 138 first-year professional bachelor's degree students in office management. They were assessed by means of portfolio assessment in a course that combined constructivist design principles and lectures. Approaches to learning and assessment preferences were measured by means of the Revised Two-Factor Study Process Questionnaire and the Assessment Preferences Inventory. Results showed that students' preferences for student participation in examination and for permanent evaluation decreased significantly. Moreover, deep approaches were not enhanced. On the contrary, surface learning increased significantly. Notwithstanding, the surface approach proved to be a significant negative predictor of the portfolio assessment score.