This paper is prepared by a Southeast Asia (SEA) specialist at the Institute for Asia and Pacific Studies, Chinese Academy of Social Sciences, in the context of the OECD Review of Innovation in Southeast Asia. It examines the current state and main trends in China’s economic relationships with Southeast Asian countries, particularly those concerning science, technology and innovation (STI).* Relations between China and SEA countries, especially economic, have developed rapidly since the 1997 East Asian financial crisis. The paper assesses the development of these bilateral economic relationships, primarily in the area of STI, over the last ten years. Section A.1 reviews current economic, trade and investment relations between China and each of the SEA countries, with a brief overview of their evolution and examination of predictions regarding the development of relations in the coming decade. Section A.2 discusses China’s strategy and policy vis-à-vis the SEA region and the region’s main economies. China considers SEA countries as crucial regional partners and hopes to deepen bilateral economic, trade and investment relationships with them in the coming decades. Section A.3 discusses existing relationships in the areas of STI, such as bilateral agreements and academic exchanges over the period 1999-2009. Section A.4 analyses the favourable factors, including political and economic aspects, and the constraints that influence the current state of science and technology (S and T) exchanges and co-operation between China and SEA countries. It appears that there have been significant achievements in the area of bilateral economic relationships, but relatively little progress in bilateral technological relationships. Section A.5 discusses future trends and directions in China’s relationship with the SEA countries in STI. It is likely that the coming decade will see relatively strong progress in technological relationships. Section A.6 discusses the role of technology assistance (S and T diplomacy) in future S and T relationships with the SEA countries. Due to certain restrictions, China’s technology assistance to SEA countries will be less than that of Japan or other more advanced economies in the East Asian region in the near future. However, it will play an increasing role in constructing bilateral economic relationships. Section A.7 sums up the main findings.