The mobility of hydration water and the dissolved oxygen permeability through different cation forms of the Nafion(R) membranes were determined. Two alkali metals (Na and K) and two amino sugars tan equivalent molar mixture of D-glucopyranosyl-alpha(1＇ --> 6)-2-amino-2-deoxy-D-mannitol and its sorbitol (GPA)and D-glucosamine (GLU)) were used as counterions. Based on the two-state model, the content and mobility of hydration water were determined using DSC and O-17 NMR. The dissolved oxygen permeability through the Nafion(R) membrane containing GPA was the lowest value in this study because, for the membrane, the fraction of hydration water was the greatest and the mobility of hydration water was the lowest. The amount and location of the hydrophilic group contained in substances as well as the kind of hydrophilic group affected the fraction and mobility of hydration water and dissolved oxygen permeability through the membranes.