The molecular transport characteristics of Santoprene rubber in the presence of n-alkanes, cyclohexane, 2,2,4-trimethylpentane, and 1,2,3,4-tetrahydronaphthalene at 25, 40, 55, and 70-degrees-C have been studied using a sorption gravimetric technique. From the sorption and desorption studies, the diffusion coefficients have been calculated and used in the discussion of the transport results. It was observed that these data depend on the size of the penetrants. Furthermore, efforts were made to evaluate the permeation coefficients, molar mass between crosslinks, and the kinetic rate constants. These data showed a systematic dependence on the penetrant size. Activation parameters for the process of diffusion and permeation have been calculated from the temperature dependence of the transport coefficients.