Over the last few years, due to their considerably enhanced properties, polymer nanocomposites have gain increasing popularity in many application areas, even in spite of their considerably higher price. One of the most important challenges at the development of commercially viable effective polymer nanocomposites is ensuring of nanosize dispersion of the used filler throughout the bulk polymer matrix at sufficiently high level of interfacial adhesion between the system’s ingredients. Purposeful modification of nanofiller and functionalization of polymer matrix both have been successfully used for increasing effectiveness of polymer nanocomposites. In the same time the research of interfacial modification of polymer nanocomposites is restricted to limited amount of polymer-nanofiller combinations. Besides it comparatively few researches consider modification of polymer blends with purposefully selected nanofillers in spite of the fact that polymer blends are increasingly used to replace individual polymers in many of everyday applications. On this score the current research is devoted to investigation of structure and elastic properties of polycarbonate-acrylonitrile-butadiene-styrene blends (PC/ABS) nanocomposites with organically modified layered silicates (OMLS). OMLS has been selected as perspective modifiers of PC/ABS blends by considering plate-like shape of the nanofillers, allowing considerably improve elastic as well as thermal and barrier characteristics of the materials primarily depending on the level of orientation within the polymer matrix. The nanocomposites have been developed on the bases of PC blend with 10 wt. % of ABS. Concentration of OMLS has been changed in between 0 and 2 wt. %. Twin-screw extrusion has been used for manufacturing of the respective nanocomposites. For the sake of better compatibility between the organic polymer blend matrix and the inorganic nanofiller certain amount of specific hydrocarbon compatibilization agent (CA) has been added. The effects of OMLS and CA on the structural, calorimetric, as well as elastic properties of the aforementioned nanocomposite compositions have been investigated.