Sulfur-resistant catalysts for selective ring opening (SRO) is an important challenge for refiners, considering the future legislation on cetane index of diesel fuels. In the present work, we performed the screening of MxSy supported on HY zeolite in gas-phase decalin hydroconversion at high hydrogen pressure (5 MPa) in the presence of 0.8% H2S concentration. Catalytic bifunctionality was investigated by changing the nature of the Transition Metal Sulfide ( TMS = Re, Ru, Rh, Ir, Cr, V and Ni sulfides were investigated). The addition of platinum group sulfides ( Re, Rh, Ir) and RuS2 improve 10 times the catalytic activity of HY zeolite alone, decreased coke deposition and dehydrogenation and increased selectivity towards RO products. For non platinum metals Cr, and V sulfides were less active but Ni sulfide present interesting properties. The reactions lead to several products families, the dominant ones being skeletal-isomerization products (SkIPs) and ring-opening products (ROPs- 1 or 2 rings opening) with a small contribution of 2ROPs. GCGC technique can unambiguously discriminate between all these C10 SkIPs and ROP products [ ]. Whatever the TMS used, the mechanism mainly proceeds from skeletal isomerization induced by the acidity of the zeolite but the hydrogen activation properties of platinum based metal sulfides are beneficial to the activity and stability of the catalyst.