Gas emission of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) from 19 commercial municipal solid waste (MSW) incinerators in China are investigated. The emission concentrations of PCDD/Fs were 0.042-2.461 ng TEQ Nm(-3) with an average value of 0.423 ng TEQ Nm(-3). The emissions of PCDD/Fs from 16 MSW incinerators were below the MEP regulation level (1.0 ng I-TEQ Nm(-3)), while only six systems have the dioxin emission levels below the limit established by the European Union Directive of 0.1 ng I-TEQ Nm(-3). The emission factors of PCDD/Fs from 19 MSW incinerators were calculated to be 0.169-10.72 microg TEQ ton(-1) MSW with an average value of 1.728 microg I-TEQ ton(-1) MSW. The total amount of PCDD/Fs emitted from MSW incinerators to the atmosphere in China was estimated to 19.64 g TEQ year(-1) in 2006.