This study examines the characterization (SEM-EDXA observation, BET measurement) and gas transport through a commercial tubular alumina mesoporous (20 and 500 Çº) support. Single gas permeation of helium (He), hydrogen (H2), nitrogen (N2) and carbon dioxide (CO2) was measured at a temperature of 450°C and feed pressures between 0.85 up to 1.0 bar. Observation of the permeance of the alumina support revealed that the transport of the gases under these conditions is governed by Knudsen diffusion. Selectivity of 2.7 was obtained for He/N2 at 1 bar. The selectivity obtained is comparable to the theoretical Knudsen value (2.65) for He/N2.