The Regenstrief Medical Record system is a computer-based medical record system for ambulatory care which has been in operation since 1973. For each patient served, it contains a core medical record including most objective data (treatment records, lab, x-ray and EKG, etc.) and selected items of subjective data. Its supports the care of patients by presenting the clinical data in clear and compact reports and by reminding the physician about clinical conditions that need corrective action. The generation of these computer reminders is totally controlled by physician authored protocols. Each protocol defines an important clinical condition and the content of the reminder to be triggered when that condition occurs. Physician compliance to the standards implicit in these protocols is improved by this feedback. Patient data are captured by computerized ancillary services, (laboratory and outpatient pharmacy) and by manual techniques. Much of these data are recorded by hand (as marks or numbers) on computer-tailored forms which can be optically read by machine. This system represents a different approach to the difficult problems of efficiently using and maintaining patient records.