The objective of this study was to estimate distribution of hazardous air pollutants and volatile organic compounds at diverse indoor areas in school. The indoor air samples were collected at 19 school in three different areas of southern Korea region from September to October 2009. The concentrations of PM-10 and formaldehyde in all sampling sites were below indoor air quality guideline of the Ministry of Education, Science and Technology. The CO2 level and TBC (total bacteria count) were higher than the guideline for 4 sites and 12 sites, respectively. The concentration of TVOC for 23 sites exceeded the guideline. Also, TVOC level of metropolitan sampling sites were somewhat higher than small and medium-size city sampling sites. The concentration of indoor air pollutants affected by various conditions such as season, region, and indoor/outdoor environment. This study result shows that concentration of several pollutants such as CO2, TBC, and TVOC were higher than the guideline for some sampling sites. Therefore, it is necessary to manage indoor air quality and establish effective emission reduction strategies regard for characteristics of each school. Keywords：Indoor air quality, Hazardous air pollutant, Total bacteria count, TVOC