Now that supply chain management has a two-decade research history, it is possible to examine the literature to identify whether there is any latent intellectual structure using bibliometric tools. The study applies a citation and co-citation approach to reveal four clusters of research that have emerged. One cluster has strong ties to the logistics field, with primarily conceptual articles. A second cluster finds its roots in operations research, and consists mainly of modeling articles. The application of multidimensional scaling, cluster analysis, and factor analysis on co-citations demonstrated a clearly identifiable structure. The structure is examined and implications for the future development of supply chain research are discussed.