Financial supply chain management and working capital management are increasingly receiving attention as important avenues to increase profitability in supply chains. By actively managing payment terms and working capital requirements, managers can influence financial performance and achieve significant cost savings. However, measures to improve financial performance implicitly restrict and influence operational performance. In our research we elaborate on the benefits of equally considering both operational and financial aspects in decision-making for the physical and financial supply chain. We develop a mathematical model that determines the optimal purchasing order quantity under working capital restrictions and payment delays. We analyze the trade-offs between the most commonly used financial and operational measurements, such as service level, return on investment, profit margin and inventory level. Our results demonstrate the significance of payment delays: Increases/decreases in the upstream/downstream payment delays favor the system's operations by decreasing operational costs. Moreover increases in the working capital employed in the system decrease the total operational cost, increase the total financial cost and lower the return on working capital investment. (C) 2009 Elsevier B.V. All rights reserved.