Recent measurements of the exhaust gases in the stacks of power plants burning coal and natural gas have shown high levels of nitrous oxide. Calculations based upon the known combustion parameters of the power plants and extrapolated to the current world production of coal and natural gas indicate that combustion may be a significant source of nitrous oxide in the atmosphere. In view of the predicted increases in the combustion of fossil fuels, particularly coal, it is likely that the importance of combustion as a source of atmospheric nitrous oxide will increase. As a result of the current uncertainty regarding the size of the varous sources and sinks of nitrous oxide in the atmosphere, it would appear that the question of the importance of combustion to the atmospheric nitrous oxide budget deserves further scrutiny.