The three cationic palladium species; Pd(1,10-phen)2(2+), Pd(2,2’-bipy)2(2+) and Pd(1,10-phen) (py)2(2+) have been immobilized in Nafion-H+ and Nafion-Na+ by ion-exchange. Characterization of the Nafion supported species has been achieved by UV, IR and C-13-NMR spectroscopies. Both Pd(1,10-phen)2(2+) and Pd(2,2’-bipy)2(2+) are unchanged when immobilized in Nafion, however, it appears that partial decomposition of Pd(1,10-phen) (py)2(2+) to give 1,10-phen and pyridine occurs in Nafion-H+. The ability of the immobilized species to dimerize ethene has been tested and the dimerization activity was found to be dependent upon the basicity of the nitrogen donor ligand and the counterion in Nafion.