This study was performed to investigate the characteristics of indoor air quality (IAQ) in 30 public facilities from February to April, 2004 in Seoul. The collected samples are PM10, formaldehyde, and total suspended bacteria in indoor air and measured by the IAQ standard method of Ministry of Environment in Korea(M.E.K). As the results of the survey, the mean concentration of PM10 was 55.19㎍/m3 in indoor air and 51.15㎍/m3 in outdoor air. The mean concentration of PM10 in the Kindergarten was higher than the IAQ standards by established by M.E.K. The mean concentration of formaldehyde was 43.08㎍/m3 in indoor air and 5.05 ㎍/m3 in outdoor air, respectively. All of them were less than IAQ standards of Korea. The concentration of total suspended bacteria in the streamer room was higher than IAQ standards. The concentration of formaldehyde was different according to the year of construction of building. Total suspended bacteria in streamer room was necessary for control. Moreover, this study was for investigation a part of indoor air pollution condition in public facilities. It means that this study can't represent for all of public facilities. Therefore, we suggest that long and middle term country plan for management of IAQ should be established through long-term and continuous investigation of IAQ condition. Keywords：Indoor air quality, Public facilities, PM10, Formaldehyde, Bacteria