The hydrogenation kinetics of N-ethylcarbazole over Ru/gamma-Al2O3 was investigated to find the rate of controlling step on the mass transfer-reaction processes. The results showed that the kinetics of reaction was controlled by the hydrogenation reaction on the catalyst surfaces. This reaction followed first-order kinetics with an apparent activation energy of 30.94 kJ/mol. The apparent kinetics model of the hydrogenation was established. Copyright (c) 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.