The emissions of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) from incineration processes has become a major. subject of considerable public and scientific concern in light of the evidence of their extreme toxicity. Efficient control of PCDD/F emissions from municipal solid waste (MSW) incineration plants requires fundamental knowledge of the pathways by which they are formed in these plants. Analytical tests conducted on several MSW incinerator residues confirmed that PCDD/Fs form in the heat recovery unit of the incinerator plant and are removed from the flue gas in the fabric filter. A mathematical model for predicting PCDD/F emissions from MSW incinerator plants was developed based on governing equations for their formation through the de novo synthesis mechanism in the post-combustion zone and their removal by the fabric filter. The PCDD/F concentrations and removal efficiencies computed using the mathematical model were also found to correspond remarkably well with plant test data.