Ring-opening metathesis polymerization (ROMP) of norbornene with most catalysts produces a polymer with an atactic placement of the cyclopentylene rings, yet partial hydrogenation of this polymer is known to yield a crystalline product. We report here a facile catalytic route to saturate polynorbornene (PN); fully hydrogenated polynorbornene (hPN) is highly crystalline, with an equilibrium melting point estimated as 156degreesC. The crystal lattice is monoclinic, with parameters a = 6.936 Angstrom, b = 9.596 Angstrom, c = 12.420 Angstrom, and beta = 130.7degrees at room temperature, indicating nearly complete extension of the hPN backbone within the unit cell. The material remains highly crystalline until the melting point is reached, but near 105degreesC, the crystal structure transforms to one characterized by substantial rotational disorder of the hPN chains about their axes, while retaining substantial translational order.