Accurate three-dimensional time-dependent quantum wave packet calculations for the N+OH reaction on the (3)A' potential energy surface [Guadagnini, Schatz, and Walch, J. Chem. Phys. 102, 774 (1995)] have been carried out. The calculations show for the first time that the initial state-selected reaction probabilities are dominated by resonance structures, and the lifetime of the resonance is generally in the subpicosecond time scale. The calculated reaction cross sections indicate that they are a decreasing function of the translational energy, which is in agreement qualitatively with the quasiclassical trajectory calculations. The rate constants obtained from the quantum mechanical calculations are consistent with the quasiclassical trajectory results and the experimental measurements. (C) 2003 American Institute of Physics.