This study was performed to investigate out-of-pocket money among medical expenses of an oriental medical university hospital by the use of internal data of an oriental hospital because medical insurance program data could not show us insuree's out-of-pocket money among medical expenses. The purpose of this study was to analyze out-of-pocket money among medical expenses of ambulatory and hospitalized patients. Under this purpose, We analyzed actual medical expenses data of 1389 out-patients and 858 in-patients of the oriental medical university hospital with 90 beds that could be approach to internal data from July 1, 1998 to March 31, 1999. The major findings are as follows : 1. In ambulatory patients, the cost share ratio of insuree & that of insurer was 90 : 10 respectly. 2. In hospitalized patients, the cost share ratio of insuree & that of insurer was 72 : 28 respectly.