Nitric oxide generation rate and concentration distribution in combustors containing regions of recirculating flow are calculated using a computer program developed for two-dimensional elliptic compressible flows. Two special techniques have been incorporated in the computer program to evaluate nitric oxide. One is the flame finding procedure by which the peak temperature lines, near which most of the nitric oxide is formed and which generally straddle the grid points of a numerical network, are located by double interpolation through local enthalpy and fuel-air composition. The other is the evaluation of nitric oxide formation in a grid volume by considering the temperature variations as well as the average temperature in the volume element. The chemical compositions, except nitric oxide, are assumed to be at local equilibrium. Methane-air equilibrium combustion tables, relating temperature and chemical species such as water vapor, carbon dioxide, and molecular oxygen to fuel-air ratio and enthalpy, are employed. Sample results for the profiles of stream function, swirl velocity, fuel mass fraction, temperature, nitric oxide formation rate, and nitric oxide concentration are presented.