In this study, bottles of mineral water and yogurt as well as Styrofoam bowls were recycled and identified by infrared spectroscopy as poly(vinyl chloride) (PVC), high-impact polystyrene (HIPS), and polystyrene (PS). Solution blending was employed to make polymer blends from these recycled plastics, including PVC/PS, PVC/HIPS/PS blends, and PVC/HIPS blends with or without a com-patibilizer, styrenelp-chlorostyrene (ST-CMS). Thermal behavior from differential scanning calorimetry was used to examine the compatibility of the blends. For the PVC/PS and PVC/HIPS/PS systems, it is found that although the third component (HIPS) may not be good enough as a compatibilizer, the addition of HIPS to the two-component blend (PVC/PS) may enhance the mechanical properties at the specific composition, especially for the blends at the intermediate concentrations. For PVC/HIPS blends with the ST-CMS copolymer as a compatibilizer, all the mechanical properties of the blends except the elongation at break, in general, increased with increasing the concentration of compatibilizer due to the increase of compatibility. The abnormal fracture strain was attributed to the differences in adhesion when various amounts of ST-CMS was added. The results of mechanical properties of the blends were consistent with the morphology from scanning electron microscopy.