Several modifications of natural rubber (NR) have been tried by Various researchers and are extensively reported in the Literature. Among these modifications, epoxidation has special significance, as it combines several important properties such as oil resistance, low air permeability, strain crystallising nature and improved damping. The effect of epoxidation on the transport characteristics and mechanical behaviour of NR has been studied in this work. Epoxidised natural rubber (ENR) with 25 and 50 mol% epoxidation level (ENR-25 and ENR-50) has been used besides NR. Different transport parameters such as rate constant, diffusion and permeation coefficients and sorption coefficient have been computed. From the temperature dependence of diffusion, activation parameters were evaluated. A comparison between theoretical and experimental diffusion results was carried out to understand the mechanism of diffusion. The polymer network structure in the swollen state has been analysed by applying the affine and phantom models. Mechanical properties of unswollen, swollen and deswollen samples were specially investigated.