To assess the processability of rigid polyvinylchloride (PVC) foam extrusion, the rheological properties of unexpanded and expandable formulations were measured by means of capillary rheometer The power law index of unexpanded formulation was 0.050 at 160℃ and 0.062 at 170℃. The power law index of expandable formulations was increased with increasing the usage level of chemical blowing agent and temperature. The pressure profile of expandable formulation deviated from straight line in the vicinity of die exit, which was more prominent with asodicarbonamide (ADCA) than with sodium bicarbonate (SBC). Inclusion of chemical blowing agent gave substantial viscosity reduction, which was also more noticeable with ADCA than with SBC.