In the literature on knowledge management (KM), one of the most important research questions is about the impact of knowledge management initiatives on firm performance. A review of research on business value of KM reveals that most of the work on evaluating the effectiveness of KM efforts is concentrated on studying the association between KM and firm performance. For several reasons, measurement of firm performance and relating it to KM efforts has proven to be a difficult endeavor. Our approach changes the focus of analysis to the process level, where the work is actually accomplished. We argue that it is worthwhile to study the effectiveness of knowledge management efforts involving KM systems (KMS's) in terms of the business processes they support. This paper proposes a KMS Value model to examine the effect of KMS's on the performance of business processes, especially those that require/can benefit from substantial knowledge sharing. We identify salient characteristics of common knowledge-intensive business processes and the metrics that can be used to evaluate their performance. The proposed model provides a clearer articulation of research questions and propositions to study the impact of KMS's on directly measurable business process performance metrics.