Information systems are part of purposeful socio-technical systems and consequently theories of action may help in understanding them. Current systems analysis and design methodologies seem to have been influenced only by one particular theory of action, which asserts that action results from deliberation upon an abstract representation of the world. Many disciplines have discussed an alternative ‘situational’ theory of action. There is no design methodology that fully supports designing systems reflecting the situational theory of action. The aim of this paper is to describe the motivation for, and progress to date of research-in-progress developing a design methodology based on concepts from the situational theory of action. This methodology for designing situational information systems is being iteratively refined using a combination of case studies and action research. This project is significant because many information systems fail in pressured routine environments where we would argue that the situational theory of action provides a better description of purposeful activity.