The reduction of NO by char from sub-bituminous SIERSZA coal has been studied in a pressurized reactor at 1073 to 1373 K. It has been found that the reaction NO + C --> 0.5 N-2 + CO is controlled both by the chemical kinetics and diffusion of NO within the char particle's pores. The rate constant of the above reaction was found to be independent of pressure within the examined range of 0.2 to 1 Wa.