Communities of practice have been heralded as a powerful knowledge management tool, especially for geographically disparate workgroups. Research into knowledge management (KM) in healthcare organizations is a needed research focus, given that differences exist in knowledge and knowledge management processes between healthcare and other organization types. The research presented in this paper examines the effectiveness of communities of practice as a knowledge sharing tool in a large and geographically disparate healthcare organization. Findings suggest that job role affects community members’ perceptions of the benefit and impact of communities of practice as well as their participation in such communities.