The advent of the World-Wide-Web protocols and client-server technology has made it easy to build low-cost, user-friendly, platform-independent graphical user interfaces to health information systems and to integrate the presentation of data from multiple systems. The authors describe a Web interface for a clinical data repository (CDR) that was moved from concept to production status in less than six months using a rapid prototyping approach, multi-disciplinary development team, and off-the-shelf hardware and software. The system has since been expanded to provide an integrated display of clinical data from nearly 20 disparate information systems.