The purpose of this study was to investigate the concentration of aldehydes from new apartments in threecities(Suncheon, Yeosu, and Gwangyang) of Chonnam region. The target apartments were within 3 months afterthe completion of construction. Aldehydes were sampled using 2,4-DNPH cartridge and analyzed by HPLC.Temperature and relative humidity were monitored continuously every one minute by digital temperature andhygrometer. As the concentration ratio of formaldehyde between back-up and front cartridge was 3.946.97%, the 2,4-DNPH cartridge method satisfied a breakthrough problem for the sample collection. Therepeatability of retention time and peak area for HPLC were excellent as 0.5 and 1.5%, respectively. Theupper floor of S apartment (16 pyong) showed the highest concentration of formaldehyde as 1,093㎍/㎥. Theaverage concentration of formaldehyde was the highest in K apartment(52 pyong) as 1,045㎍/㎥. The averageconcentration of formaldehyde in S apartment(16 pyong) and C apartment(25 pyong) were 872.6㎍/㎥ and737.5㎍/㎥, respectively. The I/O ratios of formaldehyde were 56.9 60.0(mean : 59.1), 37.9 43.3(mean :39.8) and 18.3 29.3(mean : 23.3) in K, C and S apartment, respectively. Therefore, it is believed that theindoor concentration of formaldehyde was very serious in new apartment. From these results, it is importantthat building material which emit low indoor pollutant should be selected for new apartments. In addition,management program for indoor air, such as using an adequate amount of adhesives, should be consideredand indoor optimum condition should be maintained in new apartments.