This report was done mid way through the study "A Demonstration-Cum-Research on the Reimbursement system and cost-effectiveness of Home Health Care Program in Korea". It focused on developing an estimation of early discharge day to home health care based on analysis medical records and on an analysis of medical expenses based on a detailed statement of treatment for inpatients who were hospitalized at S General Hospital in 1991. Two research methods were adopted for estimation of the early discharge day. One was micro-analysis from the medical records and the other was macro-analysis to clarify the estimated early discharge day to home health care for patients with four diseases judged from need assessment to be candidates for this type of program, namely patients with, Cesarean Section, Hypertension, Diabetes Mellitus, Chronic Obstructive Pulmonary Disease (COPD). Estimation of early discharge day to home health care were developed through many aspects of analysis of the signs and symptoms by disease in a micro-analysis in addition to a decrease in the amount of treatment, drugs, tests and changes in the test consistency, drug methods, and client's condition in the macro-analysis. Accordingly, an early discharge day for inpatients was finally estimated through the analysis of the client's conditions and treatment, drugs, tests, and nursing care activities that the patient received during hospitalization. From the research findings, the following summarized conclusions have drawn. First, for patients with Cesarean Sections, after assessing each items using the two analysis methods, the mean period of hospitalization was 8.8 days, but the mean period of hospitalization was estimated at 4.1 days if early discharge to home health care could be done. Second, for patients with Hypertension, the same method as for the patients with the Cesarean Sections was used and the result was reduction from a mean period of the hospitalization of 9.9 days to a mean period of the hospitalization of 5.2 days. Third, for patients with Diabetes Mellitus there was a decrease from a mean period of the hospitalization of 11.7 days to a mean period of hospitalization of 8.4 days if early discharge to home health care could be done. Fourth, for patients with Chronic Obstructive Pulmonary Disease, the mean period of the hospitalization was 14.3 days, but the mean period of the hospitalization could be 8.1 days if early discharge to home health care could be done.(ABSTRACT TRUNCATED AT 400 WORDS)