Bis (hydroxyethyl) naphthalate (BHEN) was polymerized to polyethylenenaphthalate (PEN) in the presence of various metallic catalysts. The influence of the nature and concentration of these catalysts on the rate of polymerization has been investigated. The order of decreasing catalytic influence of various metal ions on the polymerization of BHEN was found to be : Ti > Sb > Zn > Co > Pb > Ni (Mg). The effect of the reaction temperature has also been studied. The optimal concentration of these catalyst and reaction temperature were found to be 30 X 10(-5) (mol/mol BHEN) and 285-293-degrees-C, respectively. Because of its insolubility in ordinary solvent, the molecular weight of PEN was measured using the light scattering method.