MCM-22/MCM-41 composite, having hierarchical micro/mesoporous pore structure, was prepared using two-step synthesis method. Accordingly, mesoporous MCM-41 silica was synthesized in the presence of a delaminated MCM-22 zeolite precursor (dl-MCM-22). The structure, texture, and the acidity of the composite were compared to the corresponding properties of the MCM-22 zeolite. The hydroconversion of n-heptane was studied over the Ni,H-forms of these preparations at 240°C and 5 bar total pressure. At equal space times, regardless of the Ni-loading (Ni/H+ = ∼0.25 or 0.5), the rate of cracking was significantly lower over the composite than over the zeolite catalysts. The lower cracking activity was attributed to the faster transport of the reactants and products within the composite particles. At similar conversions similar selectivities were obtained over the compared catalysts.