Internal labour migration has become an important part of the process of China's industrialization and urbanisation in the 2000s. Using micro data for the year 2007, this chapter attempts to contribute to a better understanding of the motives of and the constraints to labour mobility in China. Drawing on various empirical investigations at the household level, it examines both the decision and the level of migration and provides a mapping of the main factors driving different types of labour mobility across space (by destination) and time (by duration).