The complexity of modern products and design tools has made the exchange of design information more complex. It is widely recognised that the seamless capture, storage, and retrieval of design information is one of the major challenges for the next generation of computer aided design tools. This paper presents a model for the flow of design information that is sufficiently formal to eventually support a semantics-based approach for developing information exchange standards. The model classifies design information into various types, organises these types into information states and levels of abstraction, and identifies the various transformations that operate within and between the information states. The model’s ability to support a variety of design process models is illustrated by applying it to the Systems Integration of Manufacturing Applications (SIMA) design process model, and the model is then applied to a design example.