In this study, a comparative study of nanocomposites with treated and untreated metal oxide nanoparticules using a plastograph was investigated. Stearic acid and co-mixing technique were chosen as a fast technique to ensure the dispersion of the filler into the polymeric matrix. Fillers were mechanically treated and co-mixed with stearic acid using kitchen coffee grinder and the mixture was then added to the polymeric matrix in a Brabender plastograph with various contents of 0.5 wt. %, 1 wt. % and 2 wt. %. The method effectiveness has been proved by AFM analysis. The results showed that the incorporation of inorganic semiconductor nanoparticles into polymeric matrix improves the dielectric properties. Results showed that with the co-mixing process and stearic acid the inorganic nanofillers have a strong influence on the permittivity of resulting nanocomposites.