Knowledge Management has been a subject of significant management interest for some 15 years. During that time it has been subjected to a variety of criticisms including the argument that it is little more than a “fad” — something that catches management’s attention for a while and then fades away because of a lack of sustainability. It has been compared to other major management fads such as quality circles and business process re‑engineering. This paper examines the discipline of Knowledge Management (KM) through the lens of management fashion theory. It demonstrates that KM is not a fad and that it has become an enduring management activity. Management Fashion Theory (Abrahamson and Fairchild, 1999) is an extension of Rogers’ Theory of Diffusion of Innovations (Rogers, 2003), that takes a skeptical view of business innovations, viewing the discourse about and the diffusion of innovations as a cultural phenomenon rather than a rational decision making process. After a brief introduction to the field of Knowledge Management (KM), a review of the theories of Diffusion of Innovations and Management Fashion is presented, along with a description of the methodology used to apply Management Fashion Theory to the discourse on KM. Bibliometric and content analysis techniques are used to examine publications and discourse in the field from 1990 to 2009. The analysis of discourse on KM demonstrates a significant period of “latency” from the late 1980s to 1994, during which foundational ideas and precursors to KM appear. Then a rapid growth period is identified, from 1995‑2001 during which KM becomes an innovation of interest to most major organizations. Finally, it appears that discourse has settled at a steady state, with no decline apparent. However, detailed analysis has also indentified a potential conflict between the interests of practitioners and researchers, with a separation of the discourse into distinct groups that may have inconsistent views on what is or is not “Knowledge Management”. In summary, this paper presents a comprehensive analysis of the evolution of discourse on KM. It provides bibliometric evidence that there has been a sustained interest in KM that is quite unlike that of other popular management themes over the last 30 years. It raises some questions about the relevance of some of the research being carried out.