A series of Ru-contained catalysts based on mesoporous and micro-mesoporous supports synthesized for the selective hydrogenation of naphthalene and tetralin in n-hexadecane solution. The influence of the support - HMS, SBA-15 and ZSM-5/MCM-41, namely porous structure and acidity on the catalysts activity were thoroughly investigated. It was found that the supports acidity has a diminutive effect on the cis-decalin formation due to increased isomerization activity of cis-decalin to trans-decalin. It was shown that the amount of unconverted tetralin influenced the final cis/trans decalines ratio considerably. The effect of parameters such as temperature, hydrogen pressure and reaction time on conversion and selectivity to partially or fully hydrogenated products was investigated under 3-7 MPa H-2, 220-320 degrees C and 0.5-3 h. It provides a practically fully naphthalene conversion and a high cis-decalin selectivity.