Swelling measurements in six organic solvents were carried out on samples of dicumyl peroxide crosslinked ethylene-propylene-diene (EPDM) having various crosslink densities. The Flory-Huggins interaction parameter chi was determined for EPDM vulcanizates 312 and 812 as well as their mixture 312/812 using the Flory-Rehner equation. The results show that the chi parameter for the crosslinked polymer is greater than for the uncrosslinked one and is a linear function of the crosslink density. The swelling behavior of the networks were also interpreted by the Flory-Erman theory using the structural factor F-4’ to characterize the network and its behavior during the swelling. The obtained chi values indicate that broadening of the molecular mass distribution, in the Gaussian region of distribution, mixture 312/812, increases interactions with solvents.