This paper proposes a study of the effects of knowledge management systems (KMS) on individual and organizational performance. The study seeks to answer the following question: Which factors determine the impact of KMS on performance by individuals and groups? A model for KMS and performance is developed. This model takes the special characteristics of KMS into account, and extends the theory of task technology fit with concepts from adaptive structuration theory. The paper presents four key propositions that are to be tested through a