Droplet behavior in the liquid-liquid extraction of nickel by mixtures of the sodium and hydrogen forms of di-2-ethylhexylphosphoric acid in toluene is reported. Mass transfer to single drops of organic phase dispersed in the aqueous has been measured. When the aqueous phase has low electrolyte concentration, visible wakes appear which are due to emulsification of the sodium salt. Mass transfer of the nickel is accompanied by transfer of water and, in some instances, by the emulsification process. The rate of mass transfer is fast and ensures some 50 pet approach to equilibrium in the residence times studied here. The effect of tributylphosphate is to improve the transfer rate but, for low electrolyte concentrations, the modifier does not remove the wakes.