To explore a medical hypermedia design process where requirements engineering and participatory design are used in a naturalistic setting, 5 years of participatory action research (PAR) have been performed in the development of a hypermedia system to be used in primary care practice. In PAR, the participating organizations cooperate with the researchers in deciding and later evaluating organizational actions, and the results are concluded cooperatively. A new type of system emerged from the study, in that the resulting design has its focus on the management of large volumes of hypermedia material, the traceability of authority in the documents, and teamwork support. Regarding the participatory design process, it was found to be essential to deal with social and organizational issues in the design group and its surroundings--and not to cover these over. For instance, an agreement was reached with the managers responsible for health care in the county where the design process took place, whereby the design activity was also given priority at the highest local administrative level. Since health care is a practice organization, there is a potential market for similar systems if only ways of organizing design and marketing the products of participatory design are further developed. Modified versions of structured product specification methods could be a valuable complement. The conclusion of the study is that the development and spread of hypermedia systems in health care may require considerable changes in current design routines and organizations.