This study investigated experimentally the effects of various operating conditions, such as bed temperature, excess air, fuel property, and the method of temperature control on NO and N2O emissions. All the experiments are conducted in a pilot scale vortexing fluidized bed combustor (VFBC). The cross section of the combustion chamber is 0.64 x 0.32 m(2), and the inner diameter of the freeboard is 0.45 m. Rice husk, soybean, and high sulfur subbituminous coal are used as fuels. Silica sand is employed as the bed material. The experimental results reveal that NO emissions increase with excess air and are almost independent of the bed temperature (600-760 degrees C). In addition, the amount of NO and N2O increases while water is injected into the combustor. The high-volatile fuel appears to form a significant amount of NO and N2O above the bed surface, However, NO emission detected at the outlet of the combustor decreases with the volatile content. Compared with the primary air, the bed temperature is the dominant factor for the trade off NO and N2O. Most of the NO is formed above the bed surface, achieves a maximum value at the position below the inlet of second air, and is reduced considerably within the freeboard. Moreover, the most remarkable feature about them is that N2O emission from combustion can be neglected no matter what the feeding material is.