Experimental results of exit plane NO/NOxemissions from atmospheric monodisperse fuel spray combustion are presented. Six different hydrocarbon fuels were studied: isopropanol, n-propanol, n-octane, iso-octane, n-heptane and methanol. The results indicate an optimum droplet size for minimizing NO/NOxproduction for all of the test fuels. At the optimum droplet diameter, reductions in NO/NOxrelative to the larger and smaller drop sizes typically were in the range of 40-70 percent. For methanol and n-octane, minimum NOxoccurred at droplet diameters of 55 and 48 μm, respectively, as compared to a 50 μm droplet size for isopropanol. The occurrence of the minimum NOxpoint at different droplet diameters for the different fuels appears to be governed by the extent of prevaporization of the fuel in the spray, and is consistent with theoretical calculations based on each fuel's physical properties. Estimates are also given for the behavior of heavy fuels and of polydisperse fuel sprays in shifting the minimum NOxpoint compared lo a monodisperse situation.