This paper describes a methodology for the participatory design of services in the public sector. The stakeholders participating in the design include three major players, the public which uses the service, the government body which sponsors and finances the service, and the organization (government or third party) that delivers the service. We propose a method for a) gathering the – possibly conflicting – requirements for a service from the three stakeholders, b) representing the design alternatives and their levels of requirement satisfaction, and c) generating a simulation model of the service delivery process for the different design alternatives. The method is illustrated by a practical example based on a real government service.