Mesoporous material, MCM-41, synthesized from rice husk (RH-MCM-41) was modified by loading silylating agent (either trimethylchlorosilane (TMCS), dimethyl-dichlorosilane (DMCS) or phenyl-trichlorosilane (PTCS)) with different concentrations (1-9 wt.%), and aging times, varied between 1, 6, 9, and 24 h. Properties of the silylated MCM-41 samples were characterized by XRD, FTIR, N2 adsorption, and the binary adsorption of a water-toluene mixture for the breakthrough curves; afterwards, the hydrophobicity indices were determined. Silylating agent caused RH-MCM-41 to possess smaller average pore size and surface area, compared to parent RH-MCM-41. Using a silylating condition of 1 wt.% TMCS for 1 h, modified RH-MCM-41 showed satisfactory enhancement its of hydrophobicity without any significant surface modification. Due to the substitution of silane group onto RH-MCM-41, the hydrophobicity index was increased.