It has been shown that it is possible to decrease fuel-NOx produced from NH3 using catalytic combustion of a synthetic gasified biomass at fuel-lean conditions. In a certain temperature regime where the conversion of fuel components, such as CO, H-2 and CH4, is low and conversion of NH3 is high, it is suggested that the formed NO, is reduced by the remaining fuel components, mainly hydrocarbons. With oxide catalysts only ca. 10% of the NH3 was converted to NO,, the rest to N-2. It has also been shown that the ignition sequence of CO, H-2 and CH4 varied for different catalysts and different experimental conditions, and that methane coupling and methanation reactions occurred before ignition of CH4.