The assessment of precipitated calcium carbonate filler dispersion in a synthetic elastomer, styrene butadiene rubber (SBR 1502), has been studied as the mixing time and rotor speed of the Brabender“ plastograph were varied. An experimental technique based on fracture surface analysis was developed in order to assess the degree of filler dispersion in the rubber matrix. The technique involved direct microscopic examination using scanning electron microscopy and the use of image processing and analysis. Dispersion index as introduced by Suetsugu was employed to quantitatively assess the degree of dispersion. The results showed that longer mixing time and/or rotor speed improved the filler dispersity throughout the rubber matrix as observed from the decreasing average particle size and the increasing dispersion indices. For instance, specimens mixed at 15 rpm for 1, 2 and 3 min have average particle size of 22.1, 19.6 and 16.8 mm and dispersion index of 0.53, 0.73 and 0.83 respectively. However, one weakness in the indexing method employed was realised as it ignored the aspect of filler distribution. This was examplified by specimens mixed at 30 rpm for 0.5 and 1 min with dispersion index of 0.72 and 0.62 respectively, while that mixed for 1.5 and 2 min have dispersion index of 0.58 and 0.66 respectively. When analysed at 45 rpm for 0.5 and 1 min, the expected increase in the dispersion index was again observed, 0.63 and 0.65 respectively.