Formation of NOX was investigated experimentally in premixed turbulent flames stabilized by a perforated plate. Gasoline, kerosene and light diesel fuel as well as their blends were investigated. During experiments, burner pressure was atmospheric and the fuel/air mixture inlet temperature was kept constant at 468 K, while both inlet mixture velocity and equivalence ratio were varied. In some experiments argon was added to combustion air to control the flame temperature. The combustion gases were sampled along the burner axis with an isokinetic probe and analysed for NOX. Experimental results showed a rapid increase in NOX in the vicinity of the reaction zone, while the rate of its formation dropped in the post flame zone. The NOX levels were affected by the equivalence ratio, the fuel type and Reynolds number. Increasing Reynolds number increased NOX formation rate, even if both the equivalence ratio and flame temperature were kept constant. This suggests that turbulent transport processes would have a dominant effect.