BACKGROUND: The "Sustainable Micronutrient Interventions to Control Deficiencies and Improve Nutritional Status and General Health in Asia" project (SMILING), funded by the European Commission, is a transnational collaboration of research institutions and implementation agencies in five Southeast Asian countries--Cambodia, Indonesia, Laos PDR, Thailand, and Vietnam--with European partners, to support the application of state-of-the art knowledge to alleviate micronutrient malnutrition in Southeast Asia. OBJECTIVE: The major expected outcomes are to improve micronutrient status on a large scale, to identify priority interventions in each Southeast Asian country, and to develop a road map for decision makers and donors for inclusion of these priority interventions into the national policy. METHODS: SMILING has been built around a strong project consortium that works on a constant and proactive exchange of data and analyses between partners and allows for the differences in contexts and development stages of the countries, as well as a strong North-South-South collaboration and colearning. RESULTS: The selection of Southeast Asian countries considered the range of social and economic development, the extent of micronutrient malnutrition, and capacity and past success in nutrition improvement efforts. SMILING is applying innovative tools that support nutrition policy-making and programming. The mathematical modeling technique combined with linear programming will provide insight into which food-based strategies have the potential to provide essential (micro) nutrients for women and young children. Multicriteria mapping will offer a flexible decision-aiding tool taking into account the variability and uncertainty of opinions from key stakeholders. The lessons learned throughout the project will be widely disseminated.