Selective ring opening (SRO) of methylcyclohexane (MCH) and methylcyclopentane (MCP) over 0.9 wt% Ir supported on USY and HZSM-5 catalysts with same SiO2/Al2O3 ratio were compared in a fixed-bed reactor. Temperature of 250-300 A degrees C, H-2 pressure of 30 bar, WHSV of 1.8 h(-1) and H-2/feed molar ratio of 40 were used for SRO. The catalysts were synthesized by impregnation method and characterized by BET, H-2-chemisorption, H-2-TPR, XRD, HR-TEM and NH3-TPD. 0.9 % Ir/USY catalyst converted 52 % of MCH into 28.6 % of ring opening products selectively, and it gave exclusively 67.4 % of ring opening products selectivity at higher 97 % conversion of MCP. In essence, the obtained catalytic results indicated superior catalytic activity for 0.9 wt% Ir/USY catalyst compared to 0.9 wt% Ir/HZSM-5 catalyst. These catalysts exhibit their stability, as well as activity even after 10 h of reaction time.