The structure of the world-economy is a central issue in world-systems research. Empirical structural analysis, however, has generally focused on a single structural aspect of the world-system: delineation of the core, periphery, and semiperiphery. This study examines another important structural facet of the world-system - blocs within the world trading order. The existence of blocs within the world-economy, as well as their configuration, have implications for states at all structural positions of the world system. Analysis of blocs which exist among core states can provide insights into issues of hegemonic cycles and decline. Outside of the core, the character of clusters can provide evidence regarding peripheral mobility, fragmentation, or subimperialism. Employing two complementary network methods, asymmetric multidimensional scaling and clique detection, this study examines blocs within the world-economy at three points since World War II: 1955, 1975, and 1994. Results indicate a somewhat multipolar, though not necessarily antagonistic, core and a somewhat fragmented periphery.