BACKGROUND: Parks are valuable community resources, and auditing park environments is important for understanding their influence on physical activity and health. However, few tools exist that engage citizens in this process. PURPOSE: The purpose of this study was to develop a user-friendly tool that would enable diverse stakeholders to quickly and reliably audit community parks for their potential to promote physical activity. A secondary aim was to examine community stakeholders' reactions to the process of developing and using the new tool. METHODS: The study employed a sequential, multiphase process including three workshops and field testing to ensure the new instrument was the product of input and feedback from a variety of potential stakeholders and was psychometrically sound. All study stages, including data collection and analysis, occurred in 2010. RESULTS: Stakeholder recommendations were combined with reviews of existing instruments to create the new Community Park Audit Tool (CPAT). The CPAT contains four sections titled Park Information, Access and Surrounding Neighborhood, Park Activity Areas, and Park Quality and Safety. Inter-rater analyses demonstrated strong reliability for the vast majority of the items in the tool. Further, stakeholders reported a range of positive reactions resulting from their engagement in the project. CONCLUSIONS: The CPAT provides a reliable and user-friendly means of auditing parks for their potential to promote physical activity. Future use of the CPAT can facilitate greater engagement of diverse groups in evaluating and advocating for improved parks and overall healthy community design.