A binary blend of acrylonitrile butadiene styrene–high-impact polystyrene (ABS–HIPS 50% wt) was prepared on a twin-screw extruder at 190–210°C. The different properties were then analyzed using tensile strength and impact tests, melt flow index, thermogravimetric analysis, and Fourier transform infrared spectroscopy (FTIR). The analysis of mechanical properties showed a decrease in elongation at break and impact strength. FTIR analysis indicated heterogeneous distribution of the blend in injected pieces and scanning electron microscopic images show heterogeneous distribution of both ABS and HIPS phase. On the other hand, by varying the percentage of styrene–ethylene–butylene–styrene (SEBS) from 10 to 30% wt using a twin-screw extruder at 190–210°C, we have prepared ternary blends of ABS-HIPS-SEBS. The addition of SEBS to the binary system ABS–HIPS allowed us to increase the ductile properties (elongation at break and impact strength), as well as reducing the viscosity.