The effect of multipass arrangement on membrane extraction through a cross-flow rectangular module has been investigated both theoretically and experimentally. In contrast to a single-pass device, improvement in mass transfer is obtained if cross-flow membrane extraction is operated in a multipass device of same configuration. It is concluded that multipass effect which provides the increase of fluid velocity, can enhance mass transfer, especially for concentrated solution with high distribution coefficient where the liquid-phase mass-transfer resistances are more extremely predominant.