A series of blends of poly(vinyl chloride) (PVC) and low density polyethylene (LDPE) are prepared and examined. Plasma treatment is applied to one of the components (LDPE) in order to affect the degree of compatibility. For this purpose, different monomers, such as carbon tetrachloride and vinyl chloride, are used. Tensile test results for all the blend samples, with and without plasma-treated LDPE, are compared. The surface energy results of blends prepared from untreated and treated LDPE-PVC showed considerable differences, with appreciable increases for the latter, indicating an increase in the work of adhesion as a result of the plasma surface modifications applied. The tensile test results and the measured surface energies are found to show a similar parallel behaviour.