A study is conducted on the effect the operating variables (temperature, space-time, steam/DME molar ratio, DME partial pressure) have on DME steam reforming over CuFe2O4/gamma-Al2O3 bifunctional catalyst in order to obtain high H-2 yield with minimum deactivation by coke. The experiments were carried out in a fluidized bed reactor under the following operating conditions: 250-400 degrees C; space-time, 0.029-1.16 g(catalyst) h/g(DME); steam/DME molar ratio, 3-8; DME partial pressure, 0.05-0.2 atm. A good balance is required between the reaction rates for both steps, DME hydrolysis (on the acid function) and the steam reforming of methanol (on the metallic function), in order to minimize the methanol concentration in the reaction medium because it promotes deactivation of the metallic function. A high steam/DME molar ratio minimizes deactivation. A steady H-2 yield of 82% along 10 h is obtained at 350 degrees C, steam/DME molar ratio of 4, and space-time of 0.58 g(catalyst) h/g(DME).