The introduction of fine powder silicas with modified surfaces into epoxy polymers was investigated. An increase in adhesive and cohesive properties was obtained. The greatest efficiency (up to 110% relative growth of adhesive strength) can be achieved by the introduction of butosil, a filler with a hydrophobic surface, and by the introduction of titanoaerosils obtained by the combined high-temperature hydrolysis of titanium and silicon chloride vapours. The mechanisms of these observed effects are discussed. The most probable causes are the decreasing inner concentration and increasing cohesive interaction as a result of macromolecular chain packing stimulated by the filler surface.