The paper describes a three-dimensional computer simulation, developed to predict the formation of nitric oxide in a tangentially fired boiler furnace burning pulverized fuel. The model was applied to a 600 MW utility boiler under different operating conditions. As fuel nitrogen is released in proportion to burnout of pulverized coal particles, the particles are treated in a Lagrangian framework in order to track burning pulverized coal particles through the gas continuum. The prediction yields encouraging results compared to experimental data.