Jointly developing a business case for inter-organizational information systems (IOS) is difficult as: (1) in a business network there are benefits that may not appear at the site where costs occur, and (2) the involved stakeholders often have different or even conflicting organizational goals. This paper analyzes the use of value modeling as a way to address these two challenges and support business case development in a network. We carried out a case study to explore the usefulness of the value modeling logic during an IOS implementation project and conclude that the integration of value modeling into business case development can help to improve the quality of the business case. The value model allows business partners to get insights into the way value is exchanged in the network and check the distribution of costs and benefits, yet doing so without having to reveal confidential details about internal business processes.