The effect of mechanochemical treatment on the hydrogenation of CO and CO 2 was studied using a flow milling vial as a catalytic reactor. Traditional catalysts for the methane formation (Ni, Zr, Zr-Ni-containing samples, Zr hydride and Zr-Ni hydrides of various genesis), as well as inactive NiO and ZrO 2, were examined. The following features of the mechanically driven CO hydrogenation were observed: (i) Zr and Zr-Ni hydrides demonstrated the highest activity in the formation of CH 4; (ii) the hydrogen present in the reaction mixture suppressed the formation of CH 4; (iii) Ni was found to be ineffective in the formation of CH 4 but active in the reaction of CO disproportionation; (iv) on the oxide samples, a small amount of CH 4 was formed owing to the mechanical activation. Deep structural transformations of the metal and hydride samples under milling in the reaction mixture were found to be responsible for the changes in their catalytic activity. Only zirconium hydride exhibited catalytic activity for CO 2 hydrogenation. In this case, no phase transformation was observed.