An extracellular polysaccharide (EPS) produced by the gram- negative nonpathogenic rhizosphere bacteria Enterobacter cloa- cae K7 was isolated and characterized. The process of biosorption of Cu(II) cations from aqueous solution by the isolated exopoly- saccharides was investigated. The maximum sorption capac- ity was 0.17 mM/mg of EPS or 12 g of Cu(II) per g of EPS at pH 5, T = 25 °C, and incubation for 30 min.