The purpose of this survey was to measure the health Service activity of the public Health Nurses and analyze the related factors influencing to their activities. The subjects of this study were 75PHN in Health Centers, Chung Buk area and survey was conducted from 15th, October to 30th, November, 1986. The results of this study were as follows; 1. General characteristics of PHN : $\cdot\;45.3\%$ of total respondents was in 30-39 age group and their average age was 34.9. $\cdot\;85.3\%$ of them were married women. $\cdot$ Their educational level was almost Nursing High School and Nursing College $(98.7)\%$. 2. Total performance average of health service activities was 2.031. Among the 11 health service categories, health service planning (2.859) and administrative service (2.489) were the most active service area. And among the specific activity items about the health service categories, the highest performed activities were. 'record & report' in health service planning (3.333 : mean), 'case finding & enrolling' in prenatal care (2.627), 'examination of health condition; in postnatal care (2.497), 'personal counselling & education' in family planning (2.560) and 'vaccination & personal education' in well-baby care (2.480). 3. There were significant difference between the performed degree of activities in department of Health Center(P<0.01). The highest health service planning activity was performed by the nurses in TB clinic and maternal care activities were carried out by MCH Center nurses. 4. PHNs in MCH Center were more active than the nurses in Health Center, which services were especially maternal and well-baby care. Their total activity score was 2.302 while 1.860 was of the nurses in Health Center. There were significant difference between their activities (P<0.01).