This study was performed to investigate the characteristics of indoor air quality (IAQ) in elementary andmiddle schools in Gyeongbuk area from July to November 2006 . The measurements of indoor air pollutantswere made to cover such components as PM-10, CO2, CO, NO2, O3, HCHO, TVOC, TBC, and Radon fromschool classrooms. The results of this study can be summarized as follows: all of them were less than IAQstandards of Korea. The mean concentration were measured by 43.0 ㎍/㎥ (PM-10), 745 ppm (CO2), 56.1 ㎍/㎥(HCHO), 350 CFU/㎥ (TBC), 0.026 ppm (O3), 0.6 ppm (CO), and 59.2 ㎍/㎥ (TVOC). Radon was not detectedin all surveyed classrooms. The I/O ratio of PM-10 was 0.8∼1.4, while that for HCHO was 5.7∼9.0.Therefore, it was concluded that the indoor pollution of formaldehyde was very serious in classroom.