A synthetic Fe-based oxygen carrier prepared by impregnation using gamma-Al2O3 as support, successfully tested for gas CLC combustion, has been now evaluated with respect to gas combustion in a 500 W-th CLC continuous unit when the fuel, CH4, contained variable amounts of H2S. Full gas combustion was reached at oxygen carrier-to-fuel ratio values higher than 1.5. The presence of sulfur in the fuel gas hardly affected the reactivity and combustion efficiency of the oxygen carrier, independently of the amount of sulfur in the gas stream. All the sulfur introduced as H2S in the fuel reactor (FR) was released in the same reactor as SO2. Furthermore, oxygen carrier particles extracted from the CLC unit after the experimental tests with H2S addition were characterized by means of different techniques and no sulfur was detected in any case. The impregnated Fe-based oxygen carrier was highly reactive and sulfur resistant, and can be considered as a suitable material for CLC with gaseous fuels that contain sulfur. (C) 2013 Elsevier Ltd. All rights reserved.