The kinetics of the initiation and propagation of the ring-opening metathesis polymerization of exo,exo-5,6-bis(methoxycarbonyl)-7-oxabicyclo[2.2.1]hept-2-ene catalyzed by Grubbs' catalyst (Cl-2(PCy3)(2)Ru=CHPh) were measured by ultraviolet-visible and H-1 NMR spectroscopy, respectively. Activation parameters for these processes were also determined. Although the ratio of the rate constant of initiation to the rate constant of propagation was determined to be less than 1 for this system, this polymerization showed many of the characteristics of a living system, including low polydispersities. (C) 2003 Wiley Periodicals, Inc.