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Advanced reburning is a NO x reduction process wherein injection of a hydrocarbon fuel such as natural gas downstream of the combustion zone is followed by injection of a nitrogen-containing species such as ammonia. The authors recently reported a seven-step, 11-species reduced mechanism for NO reduction by advanced reburning processes. However, inclusion of even a seven-step reduced mechanism into a CFD code for turbulent combustion leads to substantial computational demands. In this work, the authors have further simplified the kinetic mechanism. A simpler four-step, eight-species reduced mechanism for NO reduction by advanced reburning has been developed from a 312-step, 50-species full mechanism through the use of a systematic reduction method. The four-step reduced mechanism is in good agreement with the full mechanism for most laminar flow cases. It also agrees qualitatively with three sets of experimental data, which show the influences of temperature, CO concentration, O2 concentration, and the ratio (NH3/NO)in. It can be applied for coal-, gas-, and oil-fired combustion. The four-step reaction sequence has been integrated into a comprehensive CFD combustion code for turbulent combustion, PCGC-3. The method of integration is described. Several computations are reported with the combined code to demonstrate the predictive behavior of the advanced reburning mechanism in turbulent, pulverized coal combustion. The model calculations show the effects of temperature and concentrations of CO, O2, and NH3 on NO reduction.