Hydrogenolysis of n-butane has been studied over the (110) and (111) surfaces of Rhodium. On Rh(110), the products of the hydrogenolysis consist of methane > ethane > propane. The hydrogenolysis reaction exhibits a good fit to Arrhenius behaviour for reaction temperatures up to 500 K. At higher temperatures the reaction rate tends to ‘roll over’ due to insufficient surface coverage of hydrogen. The ‘roll over’ affects product distribution, yielding more complete hydrogenolysis to methane. The behaviour is qualitatively similar on Rh(111), with ‘roll over’ occurring at a lower temperature, namely 475 K. However, the hydrogenolysis is more selective on Rh(111), yielding 50 mol % ethane. The high ethane selectivity seen in previous work on Ir(110) is not seen on the Rh(110) surface presumably becasue the Rh surface does not exhibit the (1 × 2)‘missing-row’ reconstruction that is stable on Ir(110) surfaces under reaction conditions. The hydrogenolysis selectivity of the Rh single-crystal surfaces correlates well with supported Rh metal particles subjected to oxidation-reduction cycling.