As health care becomes more complex, interest in the benefits of coordination of care has increased. Especially patients that are being treated jointly by more than one physician (shared care), are vulnerable to adverse effects resulting from inadequate coordination and communication. We describe a study in which care providers support shared care by using computer-based patient records for data storage, and structured electronic data interchange as a means of communication. In this study, we are aiming at the development and implementation of protocols for shared care.