The purpose of this study is to analyze the effects of the health center hospital on the health service utilization pattern of the rural population in a county. Two field studies had been conducted in Yonchon County, Kyunggi Province, on February 1989 and on August 1991 before and after the establishment of the Yonchon health center hospital. This study revealed that Yonchon health center hospital occupied 7.3% of total outpatient visits and 16.8% of hospitalization of the county population and the self-sufficient rate of the outpatient visit and hospitalization of Yonchon County between two field studies increased by 1.7% and 20.9% each. Yonchon health center hospital contributed to the growth of the public health sector but it weakened the role of health sub-centers. For the efficient health service utilization of the population in that County, more investment to health center hospital would be needed and the primary health activities of the health subcenter should be enforced.