Among the many contributions of Donald A.B. Lindberg was his work on behalf of a variety or professional organizations in the field of biomedical and health informatics. These began during his early days at the University of Missouri and continued throughout his 30 years at the National Library of Medicine. This chapter summarizes that work, which occurred both through his personal efforts and through the impact of the NLM under his leadership. Examples include his role in the development of organizations themselves (e.g., the International Medical Informatics Association, the American College of Medical Informatics, and the American Medical Informatics Association) and also his contributions to the professional scientific meetings that have advanced the field (e.g., the Symposium on Computer Applications in Medical Care, MEDINFO, and the AMIA Annual Symposium).