Results　of　molecular　dynamics　(MD)　and　Monte　Carlo　(MC)　simulations　on　transport　process　of　small　molecules　in　poly　(chloro-p-xylylene)　membranes　are　discussed.　Diffusion　coefficients　have　been　obtained　by　MD　combined　with　Einstein　fluid　equation.　Solubility　coefficients　have　also　been　calculated　by　the　transition　state　Great　Canonical　ensemble　Monte　Carlo　(GCMC)　method.　Then　permeability　has　been　derived　by　diffusion　coefficient　and　solubility.　The　agreement　between　calculated　and　experimental　data　for　diffusion　coefficient,　solubility　factors　and　permeability　can　be　considered　acceptable.　Therefore,　atomistic　simulations　techniques　have　proven　to　be　a　useful　tool　for　the　understanding　of　structure-property　relationships　of　materials　and　in　particular　MD　can　be　used　for　detailed　descriptions　of　the　complex　morphologies　and　transport　mechanisms　associated　with　rigid　glassy　structures.　(C)　2010　Elsevier　B.V.　All　rights　reserved.