The miscibility of poly(vinyl chloride) (PVC) and poly(ethylene oxide) (PEO) blends wets investigated by using differential scanning calorimetry (DSC), refractive index measurements and x-ray diffraction (XRD) analysis. The negative Flory-Huggins interaction parameter, chi(12) from-the melting point depression of PEO by the blending of PVC shows that the interaction between PVC/PEO occurs. A refractive index measurement was performed to show that the miscibility of PVC/PEO blends occurs not only in solid form but also in solution form. The linear variation with composition of the refractive index of the polymer blend solutions in THF at 28 degrees C, 40 degrees C and 50 degrees C indicates the miscibility of PVC with PEO. The shift in peaks in XRD of PEO by the blending of PVC is a characteristic evidence of complexation between PVC and PEO.