Cheju Island, Korea is located in the northern East China Sea and an ideal place to monitor the transport of air pollutants in the Northeastern Asia. Organic and elemental carbon concentrations of fine aerosols were measured at Kosan, located at the western tip of Cheju Island. Between 1994 and 1996, PM2.5 particles were collected three times on a pre-fired quartz filter during the summers of 1994 and 1995 and the spring of 1996. The selective thermal oxidation method with MnO2 catalyst was used to quantify the organic and elemental carbon concentrations. The average concentrations of organic and elemental carbons are 3.74 g/m3 and 0.27 g/m3 in 1994, 2.37 g/m3 and 0.09 g/m3 in 1995, and 2.97 g/m3 and 0.32 g/m3 in 1996, respectively. The average concentration of organic carbon is higher to compare the other unpolluted areas in the world, but the average concentration of elemental carbon is comparable to those in unpolluted areas in the world. The possibility of the generation of secondary organic aerosols in the region is discussed. The long-range transport of air pollutants in this region is suggested for future study.