A new method for catalytic block copolymerization of cyclic olefins was developed for the first time. Cross metathesis was successfully utilized as a reversible chain-transfer reaction. Sequential addition of plural monomers to the polymeric terminal olefin provided a block copolymer of M-w/M-n approximate to 2.0. This paper also focuses on the development of a new crystalline-amorphous block copolymer, hydrogenated stereoblock copoly(endo-dicyclopentadiene).