Oxygen mass transfer to the aqueous Newtonian solutions of polyethylene glycol with molecular weights varying from 1500 to 20,000 was studied in a mechanically agitated vessel at constant temperature (295 K), different stirring speeds and gas velocities. The volumetric liquid side mass transfer coefficient k(L)a was determined by the dynamic polarographic oxygen electrode method. Air was used as the gaseous medium, and was introduced by a sparging regime into a mechanically agitated vessel. The influence of the molecular weight on the relationship that correlates k(L)a with the liquid viscosity as a measured function of stirring speed and gas velocity was studied. By using established gas/liquid mass transfer concepts appearing in the literature, the experimentally measured k(L)a values were correlated by the Marquardt non-linear regression analysis.