Polystyrene (PS) properties are usually tuned with the addition of elastomers and fillers to broaden the application range. However, toughening and increased tensile strength are difficult to achieve simultaneously, requiring a well-controlled particle size and distribution, as well as a good degree of intercalation and exfoliation. Therefore, the effect of the addition of a PS oligomer (PSo) to the polystyrene nanocomposite toughened with grafted Styrene-Butadiene-Styrene by maleic anhydride (SEBS-g-MA) was studied. Changes were observed in the diffractogram patterns of the nanocomposites, and a better distribution with lower alignment of the layered silicates by TEM microscopy at the presence of PSo. The storage modulus (at 25 degrees C) of the toughened nanocomposite increased approximately 12% when the oligomer was added. This result shows great potential to overcome the strong reduction (42%) when an elastomer is used in a PS blend. Also, increase in thermal degradation (35 degrees C) and impact strength (166%) were obtained.