An emulsion liquid membranes (ELMs) containing 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester (H-2 A(2)) was tested for the extraction of plutonium(IV) from aqueous nitrate solutions of different compositions. Span 80 was used as the surface-active agent and a mixture of 0.05 mol dm(-3) HNO3 + 0.3 mol dm(-3) H2C2O4 was used as the internal phase. Influence of some important experimental parameters such as exterior phase nitric acid concentration, ionic impurities in the exterior phase, concentration of H 2 A 2 in ELM phase, and organic solvents on the ELM permeation process were systematically studied. The maximum efficiency of Pu extraction among group of experiments was 98% with permeability coefficient = 0.508 min(-1) , and the corresponding concentration factor of Pu in the receiving phase was ca. 10. The stability of the emulsions was tested in the presence of different organic solvents and at different concentrations of Span 80 in LM phase. The extractions of Pu by ELM from actual and simulated waste solutions as well as in presence of some added ionic impurities were investigated. Rate of Pu extraction by ELM was studied at different treatment ratios and under repeat extractions by the same emulsion. The repeat extraction experiments showed that a concentration factor of more than 80 for Pu could be achieved.