This paper studies the effect of operating conditions in dimethyl ether (DME) steam reforming on a bifunctional catalyst synthesized with CuO-ZnO-Al2O3 metallic function and a HZSM-5 zeolite treated with NaOH to moderate acidity. The experimentation has been carried out in a fluidized bed reactor in the 225-325 degrees C range, with space time between 0.1 and 2.2 g(catalyst)/g(DME), steam/DME molar ratio between 3 and 6, and DME partial pressure between 0.08 and 0.25 bar. The 275-300 degrees C range is suitable for obtaining high values of DME conversion and H-2 yield with minimum CO formation and deactivation by coke and avoiding hydrocarbon formation. Stable values of DME conversion (0.85), H-2 yield (0.81), and H-2 production rate (180 mmol(H2)/(g(catalyst) h)) are obtained during 48 h at 300 degrees C with a steam/DME ratio of 4 and space time of 0.60 g(catalyst) h/g(DME). The main cause of deactivation is coke deposition on the metallic function.