Summary: Recycled PET as well as ABS - organomodified montmorillonite nanocomposites were prepared via melt compounding in a counter-rotating twin screw extruder. The topological changes in polymer matrices as dependency on clay modification have been evaluated from dynamic experiments in the shear flow using low amplitude oscillatory measurements. Flow characteristics of all studied organoclay nanocomposites showed shear-thinning behavior at low frequencies. Filling of PET with some organoclays led to degradation reactions, which were reflected by lower magnitudes of viscosity and storage modulus in the range of higher frequencies as compared to unfilled polymer matrix. On the contrary, no degradation during the processing of different organoclays with recycled ABS has been observed.