Samples of crystal modifications of porous silicon carbide were obtained by carbothermal method using carbon precursors (sucrose, carbon) and aerosil or mesoporous silicas molecular sieves SBA-3, SBA-15, KIT-6, and MCF as silicon sources. Porous beta-SiC samples obtained from carbon-silica composites are characterized by high structural and sorption characteristics (S (BET) up to 410 m(2)/g, V (pore) up to 1.0 cm(3)/g). High hydrogen adsorption capacity of silicon carbide samples based on KIT-6 (up to 1.24 wt% at 77 K and 1 atm.), considering low adsorption energy () up to 2.3 kJ/mol for SiC vs. ca. 5.0 kJ/mol for carbon), was determined. The highest ever reported value among the existing porous materials was observed for specific adsorption of H-2 by SiC (specific adsorption on the pore surface, rho up to 15 mu mol/m(2)) corresponding to almost complete filling of the surface with hydrogen in the examined conditions (77 K, 1 atm.).