Dynamic viscoelastic properties of a series of cyclic olefin copolymers have been investigated. The specimens differ in total molecular weight as well as molecular weight between entanglements. The angular frequency (w) dependence curves of dynamic storage and loss moduli (G(1) and G(11), respectively) of the specimens have shown that G(1) proportional to w(2) and G(11) proportional to w in the terminal region, and a plateau region at high w. On the basis of the experimental results, the dependence of total molecular weight as well as molecular weight between entanglements has been examined for zero-shear viscosity (770) and steady-state compliance (J(e)). It is shown that eta(0) proportional to M-e(1-5)(M-w/M-e)(3.5) for the melts of the copolymers in the entangled regime, M-w being the weight-average molecular weight and M, the molecular weight between entanglements. The steady-state compliance Je for the melts scales with M-e and M-w as J(e) proportional to M-e(0.5)(M-w/M-e)(0). (c) 2006 Elsevier Ltd. All rights reserved.