Experiments to investigate changes in the sorption behaviour of palladium when aged as (beta-palladium tritide for a 5.6 year period have been undertaken. The palladium was found to retain a significant quantity of the He-3 generated by the decay of tritium (He-3/Pd = 0.15) which modified the sorption behaviour. The observations corroborate previous reports of a shift in the alpha-phase boundary to higher compositions, a lowering of the plateau pressures and some tritium becoming trapped within the aged material. In contrast to previous work, no age related slope in the plateau pressures was observed and the trapped tritium was found to lower the stoichiometry of the beta-phase boundary. Crown Copyright (C) 2017 Published by Elsevier Ltd on behalf of Hydrogen Energy Publications LLC. All rights reserved.