Self-supported Pd membranes were prepared by an electroless plating method, where the membranes were separated from substrate without any damage by introducing Pd-containing sacrificial layer followed by Pd nanoparticles activation, plating and mild removal. The thickness of the obtained membranes was less than 10 m. The area was wider than 48 cm(2). Hydrogen permeation test was carried out for effective area of 2.98 cm(2). No other gas except hydrogen was detected in the permeation side by a gas chromatograph when gas mixture including H(2). CO and CO(2) was introduced into the feed side. The permeability of an obtained membrane was the same as the value of bulk Pd. (C) 2010 Elsevier B.V. All rights reserved.