In this study, a blend of polystyrene (PS)/ethylene vinyl acetate (EVA) (PS/EVA, 90: 10 wt%) was compatibilized with three different block copolymers, in which their end blocks were compatible with either styrene or EVA. The compatibilized blends with different compositions were prepared using a twin-screw extruder and injection molded into the required test specimens. Mechanical properties of the blends, such as tensile properties and Charpy impact strength, morphology of tensile fractured surfaces, rheological properties, and thermal properties, were investigated. The results show that the interaction between the dispersed and continuous phase can be improved by the addition of a compatibilizer. Appreciable improvement in the impact strength of the blend with 15 wt% of compatibilizer C (polystyrene-block-polybutadiene) was observed. Its mechanical properties are comparable to those of the commercial high-impact polystyrene, STYRON 470. (C) 2004 Wiley Periodicals.