Blends of styrene-co-butadiene rubber (SBR) and acrylonitrile-co-butadiene rubber (NBR) were prepared and their rheological and mechanical properties were examined. The effect of the addition of 5 phr of poly acrylonitrile as compatibilizer on the compatibility of the rubber blend was studied. Ultrasonic and scanning electron microscopy (SEM) techniques were used to assess the degree of compatibility of the blend. The results revealed that the use of the prepared compatibilizer has significantly resulted in the clear stability of the cure rate index (CRI) of the blends and that the tensile strength was improved at (50/50) SBR/NBR blend. The degree of compatibility was enhanced to a great extent.