The effective activation energies of CO methanation and water gas shift reactions in the Fischer-Tropsch process in the presence of cobalt catalysts supported on oxidized and unoxidized carbon nanotubes have been determined. It has been found that the energy of CO methanation does not depend on the oxidation degree of the support and varies in a narrow range from 135 to 153 kJ/mol, while the values of this parameter for the water gas shift reaction increase in the case of the oxidized support from 40 to 201 kJ/mol due to the change in the mechanism of the process.