A structured reaction system in the form of an Ni-MgO catalyst reduced to nanoscale particle size and coated on a metallic monolith proved to be an active and stable system for methane steam reforming under a steam-to-carbon ratio of 1.5 and a temperature of 700 degrees C. The catalyst-coated monolith exhibited higher stability and much higher CH4 conversion than the same catalyst in a catalyst particle bed reaction system. The high activity is attributed to the properties of the metal monolith and to the small size of the catalyst particles on the coating, while the stability is ascribed to the NiO-MgO solid solution formed in the Ni-MgO catalyst. These results are better than the corresponding ones obtained with a conventional Ni-Al2O3 catalyst reported previously [1] and comparable to the ones presented in the literature, with the advantage of working under a low steam-to-carbon ratio.