This article describes how competence-based learning (CBL) can be organised in vocational education by integrating elements from a holistic instructional design model with recent ideas on assessment. A curriculum based on this model is pre-eminently suitable for an assessment approach emphasising that proof of competence is gathered by having learners perform authentic tasks under changing assessment conditions at regular intervals. The results are stored in a so-called electronic assessment portfolio. The portfolio is constructed according to the Protocol Portfolio Scoring (PPS). The value of PPS for flexible, demand-driven vocational education is discussed. (Contains 1 figure and 2 tables.)