The phase morphology and the filler distribution in polymer blends were characterized by means of a new dynamic mechanical analyzing method. Surface treatment of carbon black and silica both effects the filler distribution in polymer blends and the resulting mechanical properties too. A treatment of carbon black with zinkdimethyldithiocarbamate results in a more equal filler distribution in a NR/BR blend. In a silica filled NR/BR blend as well as for an EPDM/BR blend, going from an in situ silanisation to pre silanisation a less enlarged filled interphase is found.