This study reports experimental results concerning the transport of permanent gases (H-2, O-2, N-2) through bitumen between 15 and 25 degreesC. A pressure differential technique, already used in membrane science in order to determine the permeability of gases through dense polymeric films, has been attempted with bitumen samples. It is shown that reproducible permeability data can be obtained thanks to this strategy, providing that bitumen mechanical resistance is improved by a support paper and a low leak module is used. Experimental results are analyzed in terms of permeability value and temperature dependency (activation energy) in comparison with other dense and permeable organic solids (polymers). The limitations of the technique as well as its potential extension to diffusion coefficient determination are discussed. (C) 2004 Elsevier Ltd. All rights reserved.