Virtual professional communities provide an environment for professionals to share their knowledge and develop their skills without geographical constraints. Virtual professional Communities became strategic instruments for enterprises, especially for the fields of Research and Development, maintenance and product development. This paper is a bibliographical research about virtual professional communities and their role for knowledge management. One purpose is to give an overview of the research work about virtual professional communities, their definition, benefits, typologies and processes. The focus of this paper is a synthesis of the literature about virtual professional communities and knowledge management. Different approaches, which discuss the integration of the knowledge management concept into the theory of virtual professional communities, are discussed.