This paper presents the results of the studies on the influence of alkali metals on the activity of ruthenium catalysts, which were supported on the products of alpha- and delta-iron oxide-hydroxide calcination. Modification of these supports with alkali metals, in particular potassium, rubidium and cesium, prior to deposition of ruthenium was found to increase the activity of Ru/Fe2O3 catalysts in the water-gas shift reaction. It was also established that the activity and stability of catalysts prepared on iron oxide obtained from alpha-FeOOH increased when the latter was modified with sodium ions. The favourable effect of sodium on the activity of the catalysts was shown to appear at a certain proportion of the base to the active component, i.e. ruthenium.