A mixture of 18-crown-6, tetrabutylammonium iodide and palmitic acid was found to be an excellent cooperative carrier for uphill transport of Pb2+ ions through a chloroform liquid membrane. In the presence of P2O7(4)- ions as a suitable metal ion acceptor in the receiving phase, it can selectively and efficiently transport lead ions from aqueous solutions containing other cations such as Cd2+, Hg2+, Cu2+, co2+, Ni2+, Zn2+, Fe2+, Ba2+, Sr2+, Ag+, K+ and Na+. Percentages of Pb2+ transport across the liquid membrane after 45 min is 97.0 +/- 1.4.