Using ring opening metathesis polymerization (ROMP) the novel linear polynorbomadiene and polynorbornene (PNB) derivatives bearing silicon-containing moieties were prepared in the presence of RuCl3.3H(2)O, RuCl2(PPh3)(3), and WCl6/tetramethyldisilacyclobutane catalysts with the yields up to 98%. Gas permeation properties (permeability and diffusion coefficients) of the polymers obtained were measured. It was shown that polynorbomadiene containing the Si(CH3)(3) group has the transport parameters similar to those of poly(trimethylsilyl norbomene) studied earlier. On the other hand, PNB bearing two Si(CH3)(3) groups in each repeat unit reveals much greater gas permeability induced mainly by increased solubility coefficients. The latter result is consistent with the much higher glass transition temperature of this polymer. (C) 2003 Elsevier Science Ltd. All rights reserved.