The Conceptual Modeling (CM) stage of an M&S study focuses on developing an abstraction of the real world for subsequent implementation as a computer model. Several studies have acknowledged the importance of CM in the success of simulation projects. Yet, there is a lack of literature on applying CM frameworks to real-world case studies, which arguably impedes the translation of CM research into practice. In this paper, we present the development of a conceptual model, using Robinson’s CM framework, for our case study investigating the perishable product of human milk within the milk banking supply chain. We present the application of the various stages of the framework, reporting on stakeholder engagement, which has allowed us to develop a shared view of the CM. The paper adds to the literature on CM in practice, providing a detailed narrative on developing a conceptual model for perishable inventory management.