Abstract: Health care information system that stores information on referee medical institutions that are of relatively large size or otherwise having high-level expertise in specific diagnostic care and diseases, and based on information input by doctors at clinics or relatively small hospitals, selects appropriate referee medical institutions. Assistance is provided when the referrer medical institution sends a referral letter; and assistance is also provided when the referee hospital sends back patient examination reports. Information on hospitals (11), (12), . . . among referee medical institutions (1) is stored in a referee hospital information database (211) at a health care information center (2). Based on patient referral information from a referrer medical institution (3), an appropriate referee medical institution is selected, and information on the selected institution is presented to the referrer medical institution (3).