The reaction pathways for NH2+NO→products and NH+NO→products have been studied theoretically, using the recently developed quantum chemical method, BAC-MP4 (Bond Additivity Corrections with fourth-order Moller-Plesset perturbation theory), which can provide accurate thermochemical molecular heats of formation and thermodynamic partition functions. In particular, we have calculated the heats of formation ΔHfo and the free energies of formation ΔGfo of the various reactants, products, and intermediates, along with the various activated complexes occurring along the reaction paths. The results indicate that NH2+NO forms a stable intermediate which can rearrange to form the products N2+H2O with no activation barrier. Also, the reaction to form NNH+OH is found to be essentially thermoneutral, making this a potential pathway, particularly at higher temperatures. For NH+NO, we find that the favored products should be H+NNO rather than N2+OH, although both can be formed with no activation barrier. Our results are also consistent with the measured activation energy for the reaction of H+NNO →N2+OH, which occurs through the same HNNO intermediate.