Coupling between pressurized gas sorption and tensile behavior was studied in several semi-crystalline polymers: a Polyethylene (PE), a Polyamide 11 (PA11) and multi-layer systems based on these two materials were tested in tension into hydrogen (30 bars) and nitrogen (30 bars) atmosphere and compared to experiments into atmospheric air. Gaseous environments were shown to have no noticeable deleterious effect influence on the modulus and the yield stress in all materials. This study provides a first basis for the mechanical design of hydrogen distribution applications. (C) 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.