Since the Kyoto Protocol became into effect, Korea has been expected to be part of the AnnexI countries performing the duty of GHG reduction in the phase of post-Kyoto. Therefore, it isnecessary to develop emission factors appropriate to Korean circumstances.In order to develop emission factors this study utilized the CleanSYS, which is the real-timemonitoring system for industrial smoke stacks to calculate the emission rate of CO2continuously.In this study, the main focus was on the power generation plants emitting the largest amountof CO2 among the sectors of fossil fuel combustion. Also, an examination on the comparison ofCO2 emission was made among 3 generation plants using the different types of fuels such asbituminous coal and LNG; one for coal and others for LNG. The CO2 concentration of the coalfired plant showed Ave. 13.85 %(10,384 ton/day). The LNG fired plants showed 3.16 %(1,031ton/day) and 3.19 %(1,209 ton/day), respectably.Consequently, by calculating the emission factors using the above results, it was found thatthe bituminous coal fired power plant had the CO2emission factor average of 88,726 kg/TJ, andthe LNG fired power plants had the CO2 average emission factors of 56,971 kg/TJ and 55,012kg/TJ respectably which were similar to the IPCC emission factor.