There is an increasing interest in exploring the opportunities for competitive advantage that arise from reinforcing core competencies and innovative capabilities of the individual companies, and by forming integrated supply networks. In complex and dynamic environments such as the automotive and semiconductor industries, managing and co-ordinating the procurement of materials, their transformation into intermediate and finished products, and the distribution to the final customers, are very demanding tasks in terms of information systems. In general, current available software packages do not provide the full support needed for networked and distributed organizations, and are clearly insufficient in what concerns the planning and coordination activities needed in these heterogeneous environments. In order to adequately tackle these problems, this work proposes a multi-agent system architecture for real-time customer-order planning in distributed manufacturing enterprises, addressing the requirements of a make-to-order environment.  The present research work resulted from the Co-OPERATE European Project. Enhanced visibility of information, early warning of disturbances, synchronized production and collaborative planning in the supply chain are the general goals of the project. In particular, for aggregate planning and order promising, a distributed and decentralized information system, based on an architecture of agents and extensively using the internet, was designed and implemented. This system aims at responding to the basic requirements of cooperativeness, integration and configurability, and at providing new and more powerful decision support.