This article proposes that professional education programmes can help promote the development of professional judgment by the use of a well-designed professional practice portfolio as an assessment tool. An explanation of the portfolio process is followed by evidence from a four-year action research study, demonstrating how compiling a professional practice portfolio enhanced students' awareness of the relationship between their practice and the theoretical and research literature in the process of developing professional judgment. The study concludes that a well-designed professional practice portfolio is a powerful mechanism for connecting workplace learning and learning in the university. Through the promotion of a disposition for reflective practice the portfolio contributed to practitioners' evolving theory of practice. (Contains 1 figure and 1 note.)