Cycloaliphatic polyolefins with functional groups were obtained by Pd(II)-catalyzed homo- and copolymerizations of norbornene derivatives. Bicyclo[2.2.1]hept-5-ene-2-carboxylic acid, the corresponding methyl ester, 2-(hydroxymethyl)bicyclo[2.2.1]hept-5-ene, and the corresponding octanoate and decanoate were used as the monomers in these addition polymerizations. Pd(II)-nitrile catalysts [Pd-(RCN)(4)][BF4](2) (with R = CH3 and C2H5) quite selectively polymerized the exo isomers of the esters of 2-(hydroxymethyl)bicyclo[2.2.1]hept-5-ene. Monomer mixtures containing an 80/20 ratio of endo/exo isomers were converted into polymers containing more than 50% of exo units. H-1 NMR studies showed that the predominant fraction of the endo isomer remained unreacted. The nitrile based Pd catalysts were not sufficiently active to polymerize the monomers with electron-withdrawing substituents linked to the bicyclic unit at ambient temperature. In-situ prepared (eta(3)-allyl)palladium complexes with associated tetrafluoroborate and hexafluoroantimonate ions were found to be substantially more active. They were able to catalyze the addition polymerization of norbornene derivatives containing a large proportion of endo isomers. Quantitative monomer conversions were achieved for aliphatic esters of 2-(hydroxymethyl)-bicyclo[2.2.1] hept-5-ene. Random copolymers of norbornene and the latter esters with molecular weights M(n)(GPC) above 100000 were prepared. The (eta(3)-allyl)palladium compounds were suitable for the polymerization of bicyclo[2.2.1]hept-5-ene-2-carboxylic acid methyl ester; high molecular weight materials were obtained via copolymerization with norbornene. Furthermore, addition polymers containing 0.2 carboxylic acid group per repeating unit were prepared by the copolymerization of norbornene and bicycle[2.2.1]hept-5-ene-2-carboxylic acid. The hexafluoroantimonate-based (eta(3)-allyl)Pd(II) catalyst had a higher polymerization activity than the Pd compound with the smaller BF4- counterion which was rationalized by a slightly stronger association of BF4- with the (eta 3-allyl)Pd(II) unit.