Supported liquid membrane (SLM) extraction of Cu(II), with di(2-ethylhexyl) phosphate in kerosene as organic phase, has been studied using a flat PTFE membrane. The influence of donor phase flow rate on the extraction efficiency and the mass transfer coefficient was investigated. The dependence of extraction efficiency of Cu(II) on the presence of the humic acids (HA) in donor phase was also investigated. The extraction efficiency decreases with increasing of humic acids concentration in donor phase, due to interaction of copper ions with humic acids. Fraction of Cu(II) binding with humic acids in donor phase was calculated using the theory of mass transfer kinetics for analytical enrichment using SLM extraction formulated by Jonsson et al. We have shown that SLM extraction can be used as a method for investigation of metal-humic acid bindings. The obtained calculated values of the binding of copper to humic acids in presence of 10 and 20 mg(.)dm(-3) humic acids in donor phase are 25.6 and 55.8%, respectively.