A computerized file system has been developed for patients admitted to the Cardiac Care Unit (CCU) at the University of Chicago, using the Slack interactive system. The records provide a reliable data base for patient care and for audit of the system. After one year's operation, 429 records were entered, and 181 of the cases were evaluated as having acute myocardial infarction. Mortality for acute myocardial infarction in this year was 11% (8% in the CCU), and the possible factors responsible for this low figure were obtained from the computer file. The system has been successful in terms of participating in the patients' care and in providing an audit, but it represents only one step on the course to a totally computerized hospital record.