Gas/liquid mass transfer has been investigated in an aerated stirred tank using non-Newtonian media and carbon dioxide as absorbent and gas phase respectively. The volumetric mass transfer coefficients at different operational variables have been measured. The non-Newtonian media (liquid phases) used were aqueous solutions of two polymers, carboxymethyl cellulose and alginate sodium salts. The influence upon the mass transfer of the rheological properties, polymer concentration, stirring rate and gas flow rate was studied. Kinematic viscosity and density experimental data were used to calculate the average molecular weight corresponding to the polymers employed. Reasonable agreement was found between the predictions of proposed models and the experimental data. The results shown in the present paper allow us to understand carbon dioxide transfer to a non-Newtonian liquid phase and to evaluate the effect of the liquid phase characteristics. The equations used in this paper allow accurate simulation of the transfer of a pure gas to a rheologically complex solution.