In addition to issues directly related to problem solving (expertise modelling, computational realisation), there are two areas which are critical for successful use of KBS technology in (medical) practice. The first area concerns the analysis of the organisation in which the KBS has to function and of the tasks in this organisation that can profit from KBS or other automated support. The second area concerns the analysis of the required interaction of a KBS with other agents, such as various types of users (expert and non-expert physicians, nurses, other health-care professionals) and other software systems. We argue that there is a need for a R&D effort towards a comprehensive methodology for medical KBS construction that covers all these areas. This ensures that KBS technology is applied for real-life problems and that users actually benefit from it. It also establishes clear routes for integrating KBS in a principled way with other medical information technology.