H istorically, ERP systems evolved from MRP II systems, which are designed to manage a production facility’s orders, production plans, and inventories. ERP systems integrate inventory data with financial, sales, and human resources data, allowing organizations to price their products, produce financial statements, and manage the resources of people, materials, and money. Implementing ERP systems can be quite straightforward when organizations are simply structured and operate in one or a few locations. But when organizations are structurally complex and geographically dispersed, implementing ERP systems involves difficult, possibly unique, technical and managerial choices and challenges. The complexities of what are often called “multisite” ERP implementations are discussed here. Like all computer-based information systems, multisite ERP implementations can be analyzed in terms of levels or layers (logical versus physical, hardware versus software). At each level there are different choices to make and different criteria for evaluating the alternatives. However, the layers are interdependent: Choices at one level may limit the available choices or affect the performance of the system at another level. Therefore, organizations are generally advised to start planning multisite ERP implementations at the strategic level before proceeding to the technical (software and hardware) levels. In practice, however, the sheer size and scale of such implementations may encourage organizations to tackle the layers MULTISITE ERP IMPLEMENTATIONS