Ground rubber tire (GRT) and its chlorinated derivative (Cl-GRT) were filled in a plasticized polyvinylchloride (PVC) compound. Themorheological studies of the PVC compound and its blends with GRT and Cl-GRT were done using a shear dynamic oscillating rheometer. Rheological complexity of the compositions was analyzed from double logarithmic plot of storage modulus (G') and loss modulus (G"). Log-log plot of complex shear viscosity (eta*) and its real component (eta') against frequency (omega) revealed higher degree of interaction between Cl-GRT and PVC compared to that between GRT and PVC. Activation energy for the flow of the PVC/Cl-GRT blend was lower than that of the PVC/GRT blend indicating retention of the network structure of the former during flow; whereas for the later lower viscosity and hence higher free volume enabled it to loose entanglement by shear force at higher temperature. PVC/Cl-GRT blend exhibited lower die swell and better extrutdate surface smoothness than those of PVC/GRT blend, when extruded at a shear rate of 900 s(-1).