The past two decades have witnessed a rapid proliferation of community-based participatory research (CBPR) projects. CBPR methodology presents an alternative to traditional population-based biomedical research practices by encouraging active and equal partnerships between community members and academic investigators. The National Institute of Environmental Health Sciences (NIEHS), the premier biomedical research facility for environmental health, is a leader in promoting the use of CBPR in instances where community-university partnerships serve to advance our understanding of environmentally related disease. In this article, the authors highlight six key principles of CBPR and describe how these principles are met within specific NIEHS-supported research investigations. These projects demonstrate that community-based participatory research can be an effective tool to enhance our knowledge of the causes and mechanisms of disorders having an environmental etiology, reduce adverse health outcomes through innovative intervention strategies and policy change, and address the environmental health concerns of community residents.