This study was to examine the effects of insurance coverage on the utilization of public health institutions and to identify the factors associated with the utilization. The data were obtained from household interview surveys conducted twice in Hwachun Gun, Kangwon Do. The time period covered in the first survey was December 17~31, 1987, before the implementation of regional medical insurance for the self-employed, and that of the second survey was January 28~February 11, 1990, after its implementation. Major findings emerged from the analysis can be summarized as follows. (1) Medical care utilization of rural people markedly increased after they were covered by medical insurance. The insurance coverage increased the utilization of public health institutions as well, and this increase was mainly attributable to the utilization by chronically ill patients. (2) Between 1987 and 1990, the proportion of the utilization of public health institutions over whole medical care utilization decreased. But the proportion increased for chronically ill patients covered by regional medical insurance during the same time span. (3) The results of logistic regression suggested that the rural self-employed utilized public health institutions at an increased rate after they were covered by medical insurance. It was also indicated that the increase resulted from the utilization by chronically ill patients. (4) The relative importance of public health institutions for rural medical care decreased after the implementation of regional medical insurance. But considering that the utilization of public health institutions by chronically ill patients increased after insurance coverage, attention should be directed to improving the capability of public health institutions to control chronic degenerative diseases.