This study analyses the future role of natural gas in the energy mix of countries of South East Europe. It identifies regional, cross-border, and country-specific gas infrastructure projects that are economically, financially, and technically sound. The study also analyses and makes proposals for the institutional and policy issues relating to funding and implementing gas infrastructure projects. The study examines sources of gas supply from Russia, the Caspian region, and other current and prospective producer countries through Turkey and other transit routes (including LNG), and it assesses costs of supply and gasification prospects in nine gas markets in the South East Europe region.