In this article an evaluation study of the development and test of a CSCW system for health care planning, is reported. The system supports the co-operative health care planning process for hospital care, primary care and municipality organised care. A CSCW system often affect informal aspects of work, and the use of the evaluation model MOA-E contributed to explain the logics of a CSCW system focussing on both work situation of the individuals, work process and quality produced to the patients. The system development was criticised for taking too long time by the stakeholders. They did not seem to understand the special characteristics of developing a CSCW system compared with a more traditional system. The evaluation model contributed to explain for the long time used for developing the system. Interviews with test users focussed their experiences of the development process. Much time has been spent on analysis of the work routines in the development work in an iterative “learning by doing” process. This participate development work has served as a learning process for the participants. The participative development style seems to be relevant for CSCW systems, but is more time consuming compared with traditional systems development.