The clinical information system architecture at the Columbia-Presbyterian Medical Center in New York is being incorporated into an intranet using Internet and World Wide Web protocols. The result is an Enterprise-Wide Web which provides more flexibility for access to specific patient information and general medical knowledge. Critical aspects of the architecture include a central data repository and a vocabulary server. The new architecture provides ways of displaying patient information in summary, graphical, and multimedia forms. Using customized links called Infobuttons, we provide access to on-line information resources available on the World Wide Web. Our experience to date has raised a number of interesting issues about the use of this technology for health care systems.