This paper discusses the process of identifying stakeholders for the evaluation of health information systems through a map. Defining the multiplicity of stakeholders associated with a new system as well as the nature of their relationships is an important aspect of evaluating any intervention. We report a study of the Electronic Prescription Service (EPS) in primary care in England. We describe the complexity associated with the process of identifying stakeholders and illustrating their dynamic relationships. Reflecting upon our experience of map-making and map-using, we discuss the role of a stakeholder map to generate and communicate knowledge. The EPS stakeholder map – in its variety of possible alternative representations – reveals the complexity of the electronic prescribing scenario and the challenge of its evaluation. Recognising the drawbacks of a static two dimensional representation, we argue that a dynamic use of a stakeholder map and a reflective map-making practice is useful and important for the evaluation of IT programmes in healthcare.