The paper reports results of the studies on the influence of lanthanum, cerium and samarium used as modifiers of carriers of the Ru/Fe2O3 catalysts on their activity in the water-gas shift reaction. It has been shown that modification of iron oxides with Sm or La ions significantly improves the activity of the Ru/Fe2O3 catalysts. The maximum activity of the catalysts has been achieved for the molar ratio of Ru:lanthanide=1:1. No correlation between the catalysts texture and their activity in the WGS reaction has been observed.