BACKGROUND: Physical inactivity is a leading risk factor for non-communicable disease worldwide. Increasing physical activity requires large scale actions and relevant, supportive national policy across multiple sectors. METHODS: The policy audit tool (PAT) was developed to provide a standardized instrument to assess national policy approaches to physical activity. A draft tool, based on earlier work, was developed and pilot-tested in seven countries. RESULTS: After several rounds of revisions, the final PAT comprises 27 items and collects information on: 1) government structure; 2) development and content of identified key policies across multiple sectors; 3) the experience of policy implementation at both the national and local level; and 4) a summary of the PAT completion process. CONCLUSIONS: PAT provides a standardized instrument for assessing progress of national policy on physical activity. Engaging a diverse international group of countries in the development helped ensure PAT has applicability across a wide range of countries and contexts. Experiences from the development of the PAT suggests that undertaking an audit of HEPA policy can stimulate greater awareness of current policy opportunities and gaps, promote critical debate across sectors, and provide a catalyst for collaboration on policy level actions. The final tool is available at www.euro.who.int/hepapat.