Gas-particle partitioning of polychlorinated dibenzo-p-dioxins, dibenzofurans (PCDD/Fs), and biphenyls (PCBs) was evaluated in flue gases emitted from two municipal solid waste incinerators. Total PCDD/Fs and dl-PCBs in the flue gas were presented, in decreasing order, within gas phases, particulate phases, and aqueous phases. PCDD/F concentrations in the flue gas ranged from 0.75 to 15 ng m–3, while in the particulate phase they ranged from 0.14 to 8.1 ng m–3. Dioxin-like (dl-) PCBs had concentrations of 0.18–28 ng m–3 in the flue gas, and 0.041–1.3 ng m–3 in the particulate phase. PCDD/F and dl-PCB levels were associated with specific size ranges of particles, increasing as particle size decreased. More than 54% (81%) of PCDD/Fs and 49% (79%) of dl-PCBs were associated with fine particles of less than 2.5 (10) µm-diameter. In addition, average levels of PCDD/Fs, PCBs, and dl-PCBs were 0.15 ± 0.11 ng m–3, 11 ± 11 ng m–3, and 0.21 ± 0.20 ng m–3, respectively. Levels of non-2,3,7,8-chlorinated PCDD/Fs were much higher than 2,3,7,8-chlorinated PCDD/Fs in PCDD/F homologue patterns. This suggests that more attention should be paid to non-2,3,7,8-chlorinated PCDD/Fs in the environment, given their potential to transform to more toxic species.