Quantum mechanical study has been carried out to investigate rotationally inelastic scattering of glycine by a hydrogen atom. In this study, the glycine is treated as a rigid body fixed in an equilibrium geometry, which results in a three-dimensional quantum scattering problem. In our study, ab initio calculations are first performed to generate potential energies in a three-dimensional (3-D) grid. These discrete energy points are used to fit into a 3-D potential energy surface using a local fitting method to generate potential energies at any given point in 3-D space. Time-dependent quantum dynamics calculation is performed to obtain state-to-state rotationally inelastic transition probabilities of glycine. The individual transition probabilities exhibit oscillatory behavior and have similar magnitude on the order of a few percent. Overall, the energy transfer between translation and rotation is generally small due to the smallness of the rotation constant of glycine. (C) 2003 American Institute of Physics.