This paper seeks to explore the loss of organizational knowledge during organizational change processes from a knowledge perspective. Recent developments in the fields of organizational change and organizational knowledge are reviewed, then the relation of organizational knowledge to discourse and power is drawn out. Using critical discourse analysis, dominant and marginalized discourses are foregrounded, different types of organizational knowledge loss distinguished, and their effects in a human services organization identified. The analysis shows how the linguistic and discursive practices of financial management are marginalizing and displacing practitioners’ organizational knowledge. An illustration is given of how situated and heuristic organizational knowledge is vulnerable to marginalization, and hence loss, as organizations seek to codify knowledge into generalizable abstractions. It is concluded that these losses of organizational knowledge are the effects of re-organizing around corporate managerialism without attention to multi-vocality and differential evaluations of worth. These findings, within a large community services not-for-profit organization, may differ in business organizations where research into knowledge management has typically focused. However, the findings are worth examining in other sites, given the migration of corporate managerialism. Organization development practitioners, consultants and leaders need to take into account both the emergent nature of change itself and how re-organizing around corporate managerialism can marginalize or lose organizational knowledge that is valued differentially. The paper’s contribution is its understanding of discursive change processes as tensions between competing bodies of knowledge. Re-conceptualizing organizational change to address such multi-vocality opens up new ways of examining how organizing and re-organizing processes in organizations affect organizational knowledge and thus organizational capability.