The present work is intended to evaluate the quality of the protein extracted from Atriplex lampa, using membrane technology. This shrub is highly available in the area studied. Ultrafiltration followed by discontinuous diafiltration was conducted, and a protein concentrate by ultrafiltration (PCU) was obtained. Then, PCU was contrasted with a protein concentrate obtained by acid thermocoagulation (PCT) through the modified Ostrowski method, suitable for forage. Results indicated that PCT was limited in its Biological Value by the sulfur-containing aminoacids with a chemical score (CS) of 79.99 for methionine + cysteine. Lysine content was remarkable, with an availability of 51%. PCU showed a CS of 82.85.A high content of the remaining essential amino acids was found, particularly that of lysine with an enhanced availability (58%). In general, PCU, when compared to PCT, had a higher protein content (850g/kg), greater salt reduction (25 g/kg), and higher availability of lysine, threonine and tryptophan. By improving the taste, its use in formulations for animal supplements is feasible. The preparation of a protein concentrate starting from leaves of Atriplex lampa is considered a potential source of protein production for animal feeding whenever the high content of salt affecting the palatability of the product can be decreased.