Nitric oxide desorption and reaction kinetics are compared on the (111), (110),and (100) planes of platinum using temperature programmed desorption mass spectrometry. NO exhibits large crystallographic anisotropies with the (100) plane having stronger bonding and much higher decomposition activity than the (110) or (111) planes. The desorption activation energies for the major tightly bound states are 36, 33.5, and 25 kcal mole −1 on the (100), (110), and (111) planes respectively. Pre-exponential factors for these states on the (110) and (111) planes are 1 × 10 16±0.5s −1. The major tightly bound state on the (100) plane dissociates to yield 50% N 2 and O 2, but all other states all planes desorb without significant decomposition. The fraction decomposed is less than 2% on the Pt(111) surface.