The hydrogen permeability of SrCe0.95Eu0.05O3 - delta and SrCe0.95Sm0.05O3 (-) (delta) was studied as a function of temperature, hydrogen partial pressure (P-H2) gradient, and water vapor partial pressure (P-H2O) gradient. Under a 100% dry hydrogen condition at 1123 K, the hydrogen permeation rates of dense membranes (1.72 mm thick) are 3.19 x 10(-9) mol/cm(2)s for SrCe0.95Eu0.05O3 - delta and 2.33 x 10(-9) mol/cm(2) s for SrCe0.95Sm0.05O3 - delta. Underwet hydrogen conditions at 1123 K, the hydrogen permeation rates are 2.89 x 10(-9) and 1.21 x 10(-9) mol/cm(2) s, respectively, for the same materials. The dopant dependence of hydrogen penneability is explained in terms of the ionization potential of the dopant. Electronic conductivity was calculated from hydrogen permeation fluxes; activation energies for electron conduction under both dry and wet conditions were also calculated. The P-H2O dependence of electronic conductivity and hydrogen permeability is discussed. (C) 2004 Elsevier B.V All rights reserved.