The effect of synthesis conditions on the phase composition and texture of porous nickel ribbon with a MgO underlayer and of nickel catalysts supported on it was studied. The MgO underlayer was prepared by impregnation of a nickel ribbon with a Mg(NO3)2 or Mg(CH3COO)2 water solutions and subsequent calcination at 750 °C in H2. The formation of more dispersed MgO was observed with the use of Mg(NO3)2 as precursor. Catalysts were prepared by supporting of nickel onto nickel ribbon with MgO underlayer by its impregnation with a mixture of solutions of Ni(NO3)2 and Mg(NO3)2 followed by thermal pre-treatment in N2 or in He. Under reduction the formation of highly dispersed nickel crystallites (3–5 nm) epitaxially bound to MgO was observed in the catalysts with MgO underlayer prepared from Mg(NO3)2 with thermal pre-treatment of the precursor of active component in N2 or He. The supported nickel catalysts showed stable activity in tri-reforming of methane throughout the test period (9 h).