The Pd-Ag membrane reformer has been packed with a Pt-based and Ni-based catalyst for carrying out the ethanol steam reforming. The experimental tests have been performed in the temperature range 400-450 degrees C: the effect of different operating parameters such as the sweep gas mode (co-current and counter-current), the spatial velocity and the water/ethanol feed molar ratio (8.4-13.0) on the hydrogen yields have been investigated. The results of these tests have been compared with the ones reported for the Pd-Ag membrane reformer using a Ru-based catalyst. With all the catalysts the best performances in terms of hydrogen yield have been attained at 450 degrees C and 200 kPa of lumen pressure with a water/ethanol feed molar ratio of 13. Especially, under these operating conditions both the Pt-based and Ni-based catalysts have exhibited hydrogen yield of about 50% against values higher than 80% reported for the Ru-based catalyst. (c) 2007 Elsevier B.V. All rights reserved.