The hydrogenation and hydrogenolysis of cyclopropane have been investigated on Ru(0001) and Ru(1120), and the kinetics of both reaction channels examined in detail as a function of temperature and the reactant partial pressures, The specific activity for propane formation was higher by a factor of 2 on the Ru(1120) substrate, whereas the activity for Ct production on this surface was lower by a factor of 1.3. The higher selectivity for hydrogenation on the Ru(1120) surface is attributed to lower hydrogen coverages on this surface and to the intrinsic higher surface carbon levels present during reaction.