This paper outlines the potential of the portfolio as a product of doctoral work, especially in the Professional Doctorates. It compares the traditional mode of a single, lengthy but clearly focused doctoral dissertation with the portfolio as a collection of shorter research reports, held together by a linking paper articulating the thesis. We argue that the portfolio is appropriate for the Professional Doctorate that focuses upon improvement in the professional workplace and that coherence and significance are key issues. (Contains 1 figure.)