The first two articles in this series outlined the widespread use of hospital surveillance for infection control programs and the potential use of surveillance for monitoring noninfectious nosocomial events. The third article focused on quality indicators as potential targets for hospital surveillance. Surveillance has been defined as the collection, collation, analysis, and dissemination of data. Several methods have been developed to perform this task in hospitals; the traditional method includes collection of data through extensive chart review, a very time- and labor-intensive process. Computerized methods have been developed for hospital surveillance: several personal computer-based programs in infection control are available, including NOSO 3 (Epi Systematics, Inc., Ft. Myers, Florida) and AICE (ICPA, Inc., Austin, Texas). In addition, the Centers for Disease Control (CDC) offer an IDEAS software program to facilitate collection of hospital data for inclusion in the National Nosocomial Infection Surveillance System. These systems offer added efficiencies in the analysis of data, but not in the collection of data. As surveillance in hospitals is expanded from infection control to other areas, more efficient means of data collection will be essential. The development and implementation of comprehensive hospital information systems offer the potential for improving, enlarging, and conducting more efficient hospital-wide surveillance. This article will review the hospital surveillance programs conducted with a hospital information system currently in use at LDS Hospital in Salt Lake City, Utah.