Introduction: the challenge of supporting health care processes Today, health care providers of all kinds face extreme pressure. Owing to demographic reasons and the availability of better medical facilities and therapy forms, expenses in the health care sector are exploding. Consequently, cost reduction is of prime importance. As a response, drastic changes in reimbursement procedures cause health care providers to act as firms with a business orientation. The ensuing competition compels health care providers either to specialize or merge, or both. A promising alternative is to build networks that enable providers to act in a corporate way vis-à-vis business partners (insurance companies or suppliers) as well as clients (patients). This situation only mirrors developments that already exist in the USA, such as health management organizations (HMOs). The question is whether new Web-based technology can improve the situation. Out of the great number of possibilities in online health provision (cf. Rippen, 2000; Rodrigues, 2000; Tambouris et al., 2000) we are interested in the design and impact of e-business at the joint between networks and patients. Our intention is to support health providers in both a cost effective provision of cross-organizational service processes and a substantial improvement in their quality. Many authors agree in that improving cooperation and coordination among different providers is of critical importance in the health care sector (e.g.