Five Finnish peats were burned in an entrained flow reactor at temperatures between 730 and 900 °C to study the conversion of peat nitrogen to nitrogen oxides (N2O, NO and NO2) in conditions simulating low-temperature, unstaged pulverized fuel combustion. Oxygen content was varied between 1 and 18 %. The major product was NO (conversion of fuel-N to NO varied between 10 and 43%), but the concentration of N2O was high at low temperatures and at 730 °C the degree of conversion of fuel-N to N2O sometimes exceeded that of fuel-N to NO. Unlike NO, the formation of N2O was not sensitive to oxygen content of the reaction environment, and it decreased with increasing ratio in the peat. This led to marked differences in the molar concentrations of N2O in the flue gas from different peats between 730 and 800 °C. Particle sizes in the range 16–205 μm and moisture contents of 5–20% had no observed effect on fuel nitrogen conversions. Conversion of fuel-N to NO2 was < 1%.