The use of coal as a reburn fuel for the reduction of NO was investigated in a 0.2 MWt pilot-scale furnace. Eight bituminous coals were selected for study over a wide range of operational parameters, including primary and reburn-zone stoichiometric ratios, reburn-zone residence time, primary-zone NO concentration, particle size and reburn-fuel fraction. Multi-variate analysis was also undertaken, to determine the importance of some of these parameters on the NO reduction observed, and the influence of reburn coal properties such as fuel nitrogen content and volatile matter. The extent of NO reduction was found to be strongly dependent on the reburn-zone stoichiometric ratio, with greater reduction in fuel-rich operation. The maximum reduction achieved was 65% and the optimum reburn-zone residence time was around 450 ms. Extending the residence time beyond 450 ms produced only a marginal gain in the maximum NO reduction. The content of volatile matter was found to be the most influential characteristic of the reburn fuel affecting reburn performance. The fuel nitrogen content was found not to be as influential a parameter for the operating conditions and coals studied.