MCM-41 and MSU-H mesoporous silicas were successfully functionalized with hydrogen bonds forming organic moieties, which have been proven by elemental analysis. Both moieties, based on oxygen and nitrogen containing groups, were introduced with high efficiencythe amount of carbon in all cases exceeded 10 % and the elemental ratios suggest binding to the surface through two or three Si-O-Si bonds. Hydrogen peroxide adsorption was conducted in its aqueous solutions and the amount adsorbed was determined using the ferric thiocyanate method. Results are presented as a function of hydrogen peroxide concentration in aqueous solution from 5 to 30 %. Both functionalized silicas show increased adsorption capacity when compared with that of their unfunctionalized analogues. The surface modified with nitrogen-based organic moiety revealed better adsorption properties as well as higher resistance against oxidation. MSU-H silica, due to its larger pore diameter, provides more space to bind hydrogen peroxide molecules and thus was found to have higher adsorption capacity: it adsorbed up to four times more hydrogen peroxide than MCM-41.