To estimate total burden of hospital admission over patient of gamily, we need to know the unofficial private expenses in addition to explicit hospital admission fees. This study was conducted from June 29, 2,000 to August 10, 2,000. Subjects were 104 patient at university hospital located at chungnam province. After thorough explanation of purpose and procedures, notebooks are given to each patient or guardian. They are requested to recorded all relevant expenditures occurred during hospital stay. Incomplete records were filled-up by direct personal contact or phones. Datas were summarized and analyzed using SAS statistical package. P-value less than 0.05 was considered significant. The results of the study are as follows: 1. In 96.1% of the patient, guardians stayed at hospital to take care of patients. In 38,8% one of the family members get work-leave or temporary resting from job. Average date of leave was 7.5days. 2. Average informal cost burden per patient was 204,467 won (14,330 won${\sim}$1,594,870 won). Average hospital cost paid by the patient was 1,061,807 won. The ratio of informal cost burden to hospital cost paid by the patient was 0.327. 3. According to the regression analysis, the relevant factors affection informal cost burdens were distance from home to hospital(p=0.018), and duration of hospitalization(p=0.0001). 4. Informal cost burden was composed of expenses for personal expense of care giver (126, 720 won/patient), meal (86,924 won/patient), transportation (77,648 won/patient), necessaries of life (18,789 won/patient), tests and treatments not covered by insurance (17,289 won/patient), medical supplies not covered by insurance (15,280 won/patient), treat for visitors (14,757 won/patient), TV coin (8,247 won/patient), and others (7,582 won/patient). In addition to the hospital cost paid by the patient for hospital admission, the informal cost burdens should be recognised explicitly because it is not small. Significant proportion of informal cost burden is composed of care-giver's personal expense, transportation, meal. It is suggested that some polices are to be devised and implemented enabling that this portion of informal expenses be directed to formal professional nursing care. Thus we can improve the quality of care and decrease discomfort of patient's relatives.