In this research, continuous SAPO-34 membranes were synthesized via secondary growth method onto both alpha-Al2O3 and mullite supports at three levels of synthesis temperature: 185, 195, and 220 degrees C for 24 h. The synthesized membranes were characterized using XRD and SEM analysis and single gas permeation experiments. It was found out that support material and synthesis temperature both have significant effects on the membrane performance. At higher synthesis temperature, SAPO-34 crystals grown over the mullite support become more uniform and smaller in size but those grown on the alpha-Al2O3 support become larger. Effect of synthesis temperature on single gas permeation properties of the synthesized SAPO-34 membranes was also studied. For the mullite supported membranes, the CH4 and CO2 permeances decrease as synthesis temperature increases; but in the case of the alumina supported membranes, by increasing synthesis temperature, CH4 and CO2 permeances first decrease up to 195 degrees C and then increase up to 220 degrees C. Even in equal membrane thicknesses, the mullite supported membrane shows lower gas permenaces. Increasing synthesis temperature decreases CO2/CH4 ideal selectivity for the alpha-Al2O3 supported membranes, while increases for the mullite supported membranes. Under optimum synthesis conditions, at room temperature and 2 bar feed pressure, the CO2 permeance through the alpha-Al2O3 and the mullite supported SAPO-34 membranes are 8.2 x 10(-7) and 8.5 x 10(-8) (mol/m(2) . s . Pa), respectively, and CO2/CH4 ideal selectivities are 51 and 61, respectively.