In this paper, the effect of the inclusion of ethylene/vinyl alcohol (EvOH) copolymer in nylon 6 is analyzed with particular attention to the transport properties. Water vapor and dichloromethane transport measurements were performed to provide useful information about polymer-polymer interaction and segmental mobility. Sorption and diffusion tests were carried out at 25°C at several activities to determine both sorption isotherm and diffusivities. Moreover, permeability tests to gases (CO2, O2) were carried out at 30°C. The obtained results indicate the existence of strong hydrogen-bonded interactions of the two polar groups (amidic of nylon 6 and hydroxyl of EvOH) within the amorphous phase. This interaction strongly influences the transport properties of the nylon 6 amorphous component.