With recognition of the importance of meeting the needs of underserved communities and the shift to more primary care-community-health workers need to be part of health teams. Community-health workers, in voluntary and salaried positions, augment the roles of professionals through outreach and community-based work and serve as liaisons between communities and institutions. This article describes the rationale for inclusion of community-health workers in research; their roles and responsibilities; and issues in their selection, training, and supervision. Examples are given from the authors' experience with interventions by nurse and community teams. Inclusion of community-health workers enriches the comprehensiveness of a holistic scientific approach to understanding health in a community.