The present paper reports the results of studies on the thermorheological properties and extrudate characteristics of the 60/40, 70/30 and 80/20 nitrile rubber (NBR)/poly(styrene-co-acrylonitrile) (SAN) blends. The effects of dynamic vulcanization and replacement of a part of the virgin NBR by a nitrile rubber vulcanizate powder (w-NBR) on the 70/30 NBR/SAN blend were also investigated. The blends show pseudoplastic behavior. Replacement of the rubber phase by w-NBR improves the die swell characteristics and surface finish of the extrudates of the thermoplastic elastomeric blend. The blends are 'thermorheologically complex'.