The emission characteristics of mercury in waste incinerators were investigated to get basic data for the policy development on the emission reduction of mercury (Hg). For the study several important factors were analysed from 4 incinerators such as mercury concentration, emission factors and removal rate for control devices. The results are listed below. Mercury concentrations in the flue gas were 0.39～5.96 $mu extrm{g}$/S㎥ in MWI and 2.5～8.8 $mu extrm{g}$/S㎥ in IWI. The distributions of gaseous and particulate mercury in flue gas were above 99% and below 1 %, respectively. Therefore, in order to remove mercury effectively, it is important to control the gaseous mercury. Mercury concentrations in fly ash collected from control device were found as 16.2～35.6 mg/kg- ash in FF of MWI. Also mercury concentrations at the front and back point of control device of MWI were 33.45～62.65 $mu extrm{g}$/S㎥ and 0.88～3.49 $mu extrm{g}$/S㎥, respectively. Emission factors were estimated as 3.67～11.67 mg/ton in FF, 2.6～24.5 mg/ton in MWI with SNCR, SDR and FF, 54.9～192.7 mg/ton in IWI with Cyclone and FF. Emissions from Municipal Waste Incinerator were found both in minimum and maximum ranges. Annual mercury emissions emitted from MWI was estimated as 20.0 kg (6.0～33.9 kg).