Hong Kong and the mainland of China (the Mainland) have maintained a close trading relationship with each other for many years. In the past decade, the Mainland was Hong Kong's largest destination of re-exports and supplier of imports. Since 2005, the Mainland had replaced the United States of America to become the largest destination of Hong Kong's domestic exports. On the other hand, Hong Kong has also played an important role in the external trade of the Mainland. This article analyses the performance and highlights the salient features of trade between Hong Kong and the Mainland during the period from 2006 to 2015.