Zirconium doped mesoporous silica (MSU) has been used as a support of Co catalysts with different Co-loadings. These catalysts have been characterised by several techniques such as XRD, XPS, textural properties, H 2 -TPR, NH 3 -TPD, chemisorption of H 2 , DRIFTS and FT-IR of adsorbed NO. The performance in the hydrogenation and hydrogenolysis/hydrocracking of tetralin at different temperatures has been examined in a high-pressure fixed-bed continuous-flow stainless steel catalytic reactor operating at 6.0MPa of pressure. The incorporation of cobalt by using the incipient wetness method with an aqueous solution of cobalt nitrate is effective for preparing catalysts with 5–20wt.% Co. The behaviour of these catalysts demonstrates that the higher the metallic loading, the contact time between catalyst and reactants, and the H 2 /tetralin molar ratio, the better the results with conversions in the steady-state near to 100% and better the yields of hydrogenation and hydrogenolysis/hydrocracking products. Thus, the catalyst with 15wt.% of Co, operating at 315°C, with a contact time of 3.6s and an H 2 /tetralin molar ratio of 15, gives rise to a conversion of tetralin of nearly 100%, yields of hydrogenation of 71%, and of hydrogenolysis/hydrocracking of 28% after 6h on-stream. In addition, the thiotolerance of these catalysts has been tested with a feed of 425 and 850ppm of dibenzothiophene (DBT). With 425ppm of DBT, the performance of the best catalyst is only reduced by 17% after 5h on-stream. However, with 850ppm of DBT, a dramatic decrease in the activity is observed, although this activity can be recovered after new thermal and reduction treatments.