In this article, we present the preparation, characterization, and catalytic performance of bimetallic Co(93)Fe(07)and Ni(80)Fe(20)active mass loaded on synthetic nanodiamonds (SNDs) in the carbon dioxide (CO2) methanation. The pristine SNDs possessing a developed specific surface are thermally stable and inert to the reaction mixture of CO(2)and dihydrogen. However, it is shown that 100% conversion of CO(2)into methane can be reached at the lower temperature than that for a massive Co(93)Fe(07)or Ni(80)Fe(20)catalyst when 20 wt.% of the catalyst mass was loaded on the surface of SNDs. The catalytic activity of the prepared bimetallic/SNDs composites is estimated as the minimum temperature at the maximum conversion of CO(2)at atmospheric pressure: it is 325 and 290 degrees C for Co93Fe07/SNDs and Ni80Fe20/SNDs, respectively. Thermal desorption studies showed that the methanation over Co-Fe/SNDs and Ni-Fe/SNDs catalysts run through the stage of CO(2)dissociation into carbon and oxygen atoms and their subsequent interaction with hydrogen to form methane and water molecules. Scanning electron microscopy studies have shown that the presence of transition metal-rich sites on the surface of the carrier contributes to the improvement of efficiency of the Ni(80)Fe(20)catalyst action.