Earlier supply chain implementations in EDI and XML have not fully supported the real time and dynamic requirements of e-procurement, in large part due to the limitations of the technologies available. The purpose of this paper is to illustrate how Web services can be used to implement a real time and dynamic supply chain operation. In particular, we focus on an e-procurement application in the context of business-to-business (B2B) supply chain integration. A prototype system has been developed to illustrate how Web services can enhance performance of the firms engaged in B2B procurement. The architecture and design of the system presented in this paper are based on a service-oriented architecture and on a three-tier enterprise design pattern. The impacts and implications of using Web services to enable real-time and dynamic business processes are also discussed.