A chloroform membrane system containing a given mixture of benzylaza-12-crown-4 and oleic acid is introduced for the selective and efficient transport of $Pb^{2+}$ ion. The transport was capable of moving metal ions ‘up-hill’. In the presence of ${S_2O_3}^{2-}$ion as a suitable metal ion acceptor in the receiving phase, the amount of lead ion transport across the liquid membrane after 150 minutes is (95.0 ${pm}$ 1.7)%. The selectivity and efficiency of lead transport from aqueous solution containing $Tl^+,;Ag^+,;Mg^{2+},;Ca^{2+},;Co^{2+},$ $Ni^{2+},;Cu^{2+},;Zn^{2+},;Hg^{2+}$ and $Cd^{2+}$were investigated. In the presence of thiosulfate as a suitable masking agent in the source phase, the interfering effects of $Ag^+;and;Cu^{2+}$ were diminished drastically.