Filler dispersion is a critical factor for the final properties of filled rubber compounds. Silica has a high density of silanol groups on the surface, which leads to flocculation and a poor filler dispersion in a rubber matrix. The hydrophobation of the silica surface by plasma-polymerization is one possibility to improve the dispersion in different polymers, without affecting the bulk properties of the filler. The surface characteristics of silica were modified by plasma-thiophene and -acetylene film deposition. The plasma-coated fillers were blended with S-SBR and EPDM, and their influence on the final vulcanizate properties was compared with untreated silica and silanized silica filled polymers. The results show a lower degree of flocculation for plasma