This work is dedicated to the steam reforming study of ethanol in a non-thermal plasma reactor at low temperature and at atmospheric pressure. The plasma reactor was powered by a high voltage 50 Hz AC power supply with a 155 mA sinusoidal current. The voltage delivered by this system was self-adjusted between 0.4 and 1 kV according to the primary voltage of the transformer. Outlet concentration species, mainly H,, CO and CO,, were determined using chemical analysis apparatus and studied as functions of the electrical power and electrical discharge characteristics. Reactor behaviour and plasma product distribution are strongly determined by the electrical power and ethanol/water ratio. Chemical species and physical parameter variations have been described using two overall reactions: the ethanol steam reforming and endothermic cracking reactions. This present paper shows interesting results in comparison with catalytic processing of ethanol steam reforming. (c) 2004 Elsevier B.V. All rights reserved.