SIA (Social Impact Assessment), both as a field of study and as an integral part of the planning process, has gained much wider acceptance and credibility in recent years in the West. Yet its implementation in the developing world should not be assumed automatic. This is because social planning in those regions has its own unique methodological assumptions and requirements. China is a case in point. This paper discusses the difficulties in implementing SIA in China under three broad areas: SIA and the planning process; its value assumptions; and its interdisciplinary characteristics. The problems are further illustrated by two case studies: the international airport plan in Shenzhen Special Economic Zone in southern China, and the Three Gorges Dam on the Yangzi River in central China.