This paper determines the potential of bentonite to replace the commonly used carbon black as filler in synthetic rubber composite product. Thus, the study made by comparing the results of curing, tensile thermal and morphological properties of bentonite and carbon black filled acrylonitrile butadiene rubber composites. The result of the tensile strength (TS), modulus at 100 % elongation (M100) and modulus at 300 % elongation (M300) for both bentonite (Bt) and carbon black (CB) filled NBR composites increased as the filler loading increased. The elongation at break (Eb) for Bt followed the same trend but not for NBR/CB composites. At similar filler loading, CB filled acrylonitrile butadiene rubber (NBR) composites demonstrated higher TS, M100, M300, and Eb compared to the Bt filled NBR composites. As the filler loading increased, the swelling percentage decreased for both types of fillers. However, at similar filler loading, the swelling percentage of CB filled NBR (NBR/CB) is lower than the Bt filled NBR (NBR/Bt). Scanning electron micrograph (SEM) of the tensile fractured surface of NBR/CB composites exhibits better filler dispersion and more tear lines compared to the NBR/Bt composites.