Traditionally, China and North Korea have been described as ‘blood brothers’ because of their common socialist ideological ground. Since 2000 the basis of their relationship has shifted from one-sided economic support by China into strategic and mutual cooperation. In this paper, we analyse changes in their relationship by examining two specific points: first, China's growing investment and trade in North Korea, and second, close linkages of regional development strategies between the two countries. While the prevalent discussions around North Korea and its relations with China concentrate on geopolitical issues, this research shed more light on geoeconomic engagement between China and North Korea. This paper argues that it is crucial to grasp how China and North Korea perform geoeconomic calculations toward each other and how this affects geopolitical conditions.