We report on a pilot project implementing electronic data processing (EDP) in the Department of Cardiac Surgery of the University of Heidelberg, based on a concept of complete integration of a medical database system into everyday clinical routine. A computer network was installed and has been in use since August 1988 as a department system supporting both the administrative and the medical side of the department (documentation, information, research, archives, organization, secretarial office, billing, statistics and communication). With a computer-assisted documentation system and standardized data acquisition, nearly 80% of letters and reports on operations are written automatically without any further need for dictation. Automatic computer controlled follow-up has been initiated to cover all patients operated on in our hospital. The complete integration of a new method of clinical documentation and EDP into everyday clinical routine and the extensive use of computer-derived information have proved to be significant advances. Our practice of computer-assisted information management and departmental organization serves the patient by; (1) providing up-to-date valid information for the clinical staff; (2) establishing and stabilizing contact and communication with physicians elsewhere, e.g. cardiologists; (3) facilitating pre- and postoperative contact with patients; (4) helping to optimize medical treatment by routine statistical data analysis (quality assurance); (5) creating a clear and logical computer-assisted departmental organizational structure; (6) permitting long-term evaluation of operative results based on a standardized computer-controlled follow-up procedure; (7) improving the quality of medical and administrative data.