In this article we analyse the location patterns of firms that provide specialized advanced producer services (APS) to international commodity chains that move through seaports. Such activities can take place in world cities or in port cities. The analysis of APS location patterns in port cities provides a good opportunity to integrate the study of world cities into the framework of Global Production Networks. Based upon our empirical findings, we conclude that while port-related APS activities predominantly follow the world city hierarchy, a number of port cities stand out because they act as nodes in global commodity flows and as centres of advanced services related to shipping and port activities. Based on these empirical findings we add...