In considering structural materials for fusion reactors a detailed understanding of the transport parameters and solubility of hydrogen and its isotopes is an important issue which deal with safety and blanket performance aspects. The experimental activities were focused on the determination of hydrogen/deuterium transport parameters through Eurofer 97 in the temperature range 423+723K using a time dependant permeation technique The hydrogen permeation and diffusivity at room temperature and density of trapping sites were also evaluated using Devanathan's technique. Hydrogen / deuterium permeation experiments on Eurofer 97 showed a non-negligible decrease in permeability with respect to other fusion oriented martensitic steels, even if it remains about one order of magnitude higher compared with that of austenitic AISI 316L steel.