Supply Chain Management (SCM) is extremely important to the manufacturing and retailing industries. Profitability of enterprises in these two industries depends on the efficiency and effectiveness on they manage their supply chains. Information technology has been a key element in supporting supply chain management. As the access to the Internet becomes easier, managers are able to access real-time data and use decision support tools to support their decision making. In this paper, we investigate how multi-agent technology and constraint network can be integrated together to improve the efficiency and transparency of supply chain management. A multi-agent based supply chain management system has been developed to support communication, coordination, collaboration, and operation of different entities in supply chains. Which enabled the warehouses and plants to query and share information. A constraint network model has been applied to model the objectives and constraints of each entity in supply chains. Two experiments have been conducted to evaluate the usefulness and performance of the system with participation of a retailing firm. The results indicated that the proposed system has several benefits. For example, improve efficiency by saving time and efforts for decision makers as well as improve the quality and responsiveness of decision making by value-added services, such as, bullwhip detection agent.