Dispersion of compounded ingredients in a rubber formulation is important for fatigue or tensile performance. After mixing, certain compounds can remain as dispersed phases within the rubber matrix, which will lead to critical flaws, influencing performance according to the Griffith equation. High Resolution X-Ray Computer Tomography offers a unique opportunity to measure phase domain size and distributions when sufficient x-ray contrast exists. Fillers such as carbon black or silica can be differentiated from sulfur and zinc oxide providing an opportunity to determine dispersion characteristics of the various phases. High-Resolution X-ray Computed Tomography has become an important characterization tool for 3-D and higher dimension material science relatively recently due to the availability of polychromatic micro-focus x-ray sources, efficient and high spatial resolution detectors with superior scintillators. HR-XCT provides very rich data quantifying mixing efficiency of particulates in a matrix, such as insoluble sulfur or silica particles in rubber. Imaging with x-rays provides attenuation, phase, or scattering contrast and will prove to be a critical method for evaluating the field of rubber crosslinking, considering realistic environments in-situ. This paper will highlight methodology development, validation and provide insight on the ability of dispersion of Crystex™ Cure Pro in typical rubber formulations. This straightforward approach will illustrate opportunities for higher productivity in both product evaluation and ultimately tire plant operations.