The reaction of sodium borohydride with steam produces hydrogen gas and a hydrated solid. Unlike the reaction in liquid water, up to 95% yield of hydrogen is obtained with pure steam without a catalyst. Liquid promoters (methanol and acetic acid) at concentrations of 1 mol% do not enhance the reaction rate, although acetic acid improves the hydrogen yield slightly. (c) 2007 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.