Within public health, there is a tradition of co-operation between researchers and communities in planning and implementation of health promotion programs. As a consequence, public-health organizations are characterized by having complex multidisciplinary structure and dynamic organizational goals. In this paper, we discuss the economic impacts from the use of Participatory Design for development of public-health information systems. Creation of systems that have both utility and usability is suggested to be highlighted as the central goal. The identified prerequisites for a positive impact are that the new system should be of high quality, appropriate to the nature of the health promotion tasks, and to how activities are coordinated and integrated both between and within the stakeholder groups involved. We argue further that a method that minimizes the information asymmetry in the development process is necessary for avoiding market failures. The conclusion is that participatory design will diminish transaction costs, will help to avoid sunk costs, and will contribute to rich efficient use of human and economic resources in public-health organizations.