In this study, exploration of possibilities for use of recycled poly(ethylene terephthalate) (PET) in powder form as a filler in the PVC matrix was made. Powdered PET surfaces were modified by plasma to enhance the degree of interaction and, hence, the compatibilities. For modification, a series of different chlorine-containing monomers at two plasma operational conditions selected were used, in addition to the direct use of an oligomer of vinyl chloride. A series of mechanical, thermal, and surface energy analyses made with the composite samples prepared showed that it is possible to improve the properties by employing proper surface modification, which, in some cases, can even lead to synergestic results.