In this study, the effects of equivalence ratio and nitrogen dilution on laminar burning velocity were studied for propane/air/nitrogen mixtures. The stretched laminar burning velocity of mixtures was determined from the measured pressure histories in a constant volume spherical chamber. The effect of stretch rate on the laminar burning velocity was analyzed using linear and nonlinear methods. The laminar burning velocities of the diluted mixtures decreased with an increase in volume percent of nitrogen dilution. The laminar burning velocity of diluted mixtures was lower than that of lean mixtures in the same propane concentration.