Chemically crosslinked polycyclooctene having excellent shape recovery properties is prepared by ring-opening metathesis polymerization of cis-cyclooctene followed by chemical crosslinking. The crosslinked polycyclooctene can be shaped, the shape memorized, a new shape imparted with the original shape being recoverable by suitable temperature adjustment. The dependence of shape memory characteristics on degree of crosslinking was established. In addition to polycyclooctene, blends thereof with other materials such as SBR, EVA, polyurethane rubbers, and inorganic fillers can be utilized to provide chemically crosslinked products having excellent and tailored shape memory properties.