The overall aim of this document is to provide a foundation for understanding the opportunities and potential risks of harmonization of environmental regulation and regulatory practice across Australia. The focus adopted was intra-national harmonisation of environmental laws. A multi-method approach was undertaken including the following: 1. Desktop research and review of relevant literature and legislation; 2. Key informant data from discussions with members of the Harmonisation of Environmental Regulation Project Team; and 3. Three case studies: US Pollution, NSW Planning and Hazardous Waste.