Knowledge and Knowledge Management (KM) are gaining more and more attention in theory and practice. This development can be observed by an increasing number of publications since the 1990s, addressing the question of how knowledge in organizations can be organized and managed (Davenport & Prusak, 1998, Nonaka & Takeuchi, 1995). It is argued that knowledge is becoming the pre-eminent source of competitive advantage compared to the traditional factors of production, labour, capital and land. This theoretical discourse is accompanied in practice by an increasing number of KM initiatives. In many cases however, the results of those KM implementation projects have not lived up to the high expectations associated with them. Reasons for that are manifold. In this article, we will present the results of an extensive analysis of KM literature identifying the major barriers to KM. Those barriers represent current challenges during any holistic KM implementation that includes knowledge management systems (KMS).