Methane or natural gas is a practical alternative fuel of vehicles. To develop more efficient technology of on-board storage, a possibility of using SBA-15 as the methane carrier is tested. An ordered mesoporous silica molecular sieve SBA-15 is synthesized aimed at collecting the data of methane sorption in the presence of water. The synthesized material is examined with SEM, TEM, and XRD analyses, and the hexagonal channel structure is confirmed. Its textual parameters are evaluated on the basis of the adsorption data for nitrogen at 77 K, and it gives the results of 802 m(2)/g for the specific surface area, 1.31 cm(3)/g for the pore volume, a narrow pore size distribution centered at 7.7 nm. and 4 nm for the width of the partition wall. Methane sorption isotherms on SBA-15 are collected with a volumetric method for samples of different contents of water, and the enhancement of the sorption capacity due to the presence of water is observed. A discussion on the mechanism of the sorption enhancement is presented.