A novel type of liquid-liquid contactor was developed in which a DC electric field effectively functioned by dispersing an aqueous phase very finely into an organic phase, agitating the organic phase with the droplets and separating both phases. That is, the hydrodynamic behaviour was performed without any other means such as liquid dispersers, agitators and settlers. Both phases contacted satisfactorily in a crosscurrent flow in the contactor. The population behaviour of the droplets in the contactor was examined in terms of the dispersed phase holdup and the size distribution of the droplets. The droplet size in the electric field showed different results in the absence and in the presence of mass transfer. The extraction characteristics of praseodymium (Pr) and neodymium (Nd) from an aqueous phase containing a water soluble complexing agent (EDTA, DTPA and their mixtures) to an organic phase (ISOPAR M) containing an extractant (D2EHPA) were also experimentally examined. Mass transfer results showed that the higher the applied voltage, the better was the degree of separation of both metals. This is attributed in part to an increase in the frequency of the coalescence-redispersion of the droplets and of the droplet formation.