The objective of this work is to study the transfer of oxygen from gas to liquid phase in an electroflotation cell. The measurements were performed in a laboratory scale cell using insoluble electrodes, titanium coated with ruthenium oxide as anode and stainless steel as cathode. The volumetric mass transfer coefficient K(L)a, was characterized for clean tap water as liquid phase for different values of current density (J). The global coefficient of mass transfer based on the liquid film, K-L, and the specific interfacial area, a, were characterized. A model which relates KLa to current density was established. Different evaluation criteria of oxygen transfer in electroflotation process were determined and compared with other aeration process.