One of the major problems in extrusion die design is flow balancing. Simulations for balancing die flow are directly affected by rheological data of the material. Rheological data for polymer processing are mostly based on piston-type capillary rheometer data. Piston-type capillary measurements are off-line, and it does not reflect the extrusion process conditions. For this reason, in this study the availability of in-line screw type capillary rheometer in thermoplastic elastomer (TPE) rheological characterization was experimentally studied. The results reveal that in-line rheological characterization methods are more realistic than the off-line methods.