In situ XAS at the Ru K edge was used to study the reductive sulfidation (15% H2S/H-2) of Ru(NH3)(6)(3+) supported on HYd zeolite, and the evolution of the sulfided sample under working conditions (lower H2S partial pressure, addition of toluene to the feed). Sulfidation starts at room temperature and is complete at 373 K. At that temperature, the sample is fully sulfided (5.9 S neighbours per Ru). Above 423 K a partial surface reduction (4.3 S neighbours per Ru), and the formation of metallic ruthenium (3.3 Ru neighbours per Ru) are observed. The evolution under working conditions shows that the local structure is not significantly modified when the H2S partial pressure is decreased and especially that it does not lead to an increased reduction. Upon addition of toluene the intensity of the Ru-Ru peak in the FT EXAFS spectra is modified, whereas the RuS peak remains unchanged. This is indicative of the chemisorption of toluene on the metallic sites and points out the prominent role of these sites for aromatics hydrogenation. (C) 2007 Elsevier B.V All rights reserved.