DUCRUET C., KOSTER H. R. A. and VAN DER BEEK D. J. Commodity variety and seaport performance, Regional Studies. Seaports are key locations within value chains and production networks. Port policies of national and local governments seek higher rents through strategies of specialization or diversification. Elaborating on longstanding research about urban and regional development, this paper proposes an empirical investigation of the interplay between traffic variety and port performance. The analysis of traffic data per commodity for 330 European ports highlights the influence of multiple factors such as location, function, and local context, together with the specificity of some commodities regarding port evolution. The demonstrated importance of territorial factors provides a good complement to the existing literature mostly focused on global networks and economic players. © 2010 Regional Studies Association.