The incorporation of 5-vinyl-2-norbornene (VNB) into ethylene-norbornene copolymer was investigated with catalysts [Ph2C(Fluo)(Cp)]ZrCl2 (1), rac-[Et(Ind)(2)]ZrCl2 (2), and [Me2Si(Me4Cp)(BuN)-Bu-t]TiCl2 (3) in the presence of MAO by terpolymerizing different amounts of 5-vinyl-2-norbornene with constant amounts of ethylene and norbornene at 60 degreesC. The highest cycloolefin incorporations and highest activity in terpolymerizations were achieved with 1. The distribution of the monomers in the terpolymer chain was determined by NMR spectroscopy. As confirmed by XRD and DSC analysis, catalysts 1 and 3 produced amorphous terpolymer, whereas 2 yielded terpolymer with crystalline fragments of long ethylene sequences. When compared with poly(ethylene-co-norbornene), VNB increased both the glass transition temperatures and molar masses of terpolymers produced with the constrained geometry catalyst whereas decreased those for the metallocenes.