Project abstract: The tobacco products consumed by the world's one billion smokers are highly engineered, meticulously marketed and, for about 50% of users, lethal. More so than many other dangerous products, regulating tobacco manufacture, labeling, sale, distribution, advertising and promotion has proven particularly challenging in many contexts, even with strong legislation like the Family Smoking Prevention and Tobacco Control Act (Tobacco Control Act), P.L. 111-31. Through this project, WHO will use its unique history, position, networks and contacts in international tobacco control and tobacco product regulation efforts to support the Food and Drug Administration (the FDA) in its approaches to reducing tobacco use, harm and addiction. WHO's experience in this area includes managing the Study Group in Tobacco Product Regulation (TobReg), the Tobacco Laboratory Network (TobLabNet), its Collaborating Centres in Tobacco Product Regulation, the Global Tobacco Regulators Forum (GTRF), and, for the past three years, the WHO-FDA Cooperative Agreement ?Building Research Capacity in Global Tobacco Product Regulation Program?. Building on lessons learned and these extensive networks, this project proposal sets out a number of science-based activities over the next five years. These include development and coordination of multilateral research efforts in science, law, policy and public health communications. Because sound data is the cornerstone of good regulation, activities will also expand data collection and information sharing mechanisms, management and reporting protocol. A separate reporting activity will ensure that WHO carefully monitors and evaluates program activities, processes and outcomes. As the FDA's Center for Tobacco Products (CTP) considers its mandate to place restrictions on the sale and distribution of tobacco products, implement tobacco product standards, review applications for new tobacco products, and consider applications for modified risk products, the information from this project will enable US regulators to consider global trends, existing and new scientific literature, and relevant evidence/information from other countries. Since CTP now has authority to regulate all tobacco products, including novel products that may not be on the U.S. market yet, it is particularly important to learn from other regulators and researchers with relevant experience.