The high amino acid content (lysine, meteonin and tryptofan) of most leaf proteins makes them suitable as supplements for cereal flours, which are deficient in these amino acids. These proteins are used in cattle balanced foods. In this work, separative membrane technology, ultrafiltration (UF) and discontinuous diafiltration (DID), was used to obtain a protein concentrate from an aqueous extract of Atriplex lampa, a chenopodiaceous shrub abundant in the and and semi-arid regions of the Province of San Luis, Argentina, for the purpose of improving its palatability, affected by its high salt content. The parameters and operation conditions were studied in the pretreatment of feed as well as in UF process to obtain maximum performance. This procedure was found to be a convenient method for concentrating soluble protein contained in aqueous extract of "zampa", using inorganic membranes of 15 kD molecular weight (MWCO). The final concentrate was dried on a vacuum stove at 35degreesC. The concentrate had a protein content of 71% (dry weight basis) and a marked decrease of salt content, from 38% in the leaf to 2.1% after processing. No adsorption or critical fouling phenomena were observed during the process, which allowed performing a conventional wash cycle to restore the initial conditions of the membrane.