In order to remove the toxic quinolizidine alkaloids and other nonprotein constituents, hexane-defatted flakes of lupin (Lupinus rautabilis) were extracted under various conditions with ethanol, methanol or their aqueous solutions. Lupin protein concentrates containing more than 70% protein and 0.1-0.2% alkaloids were obtained in high yields by consecutive extractions, countercurrent extraction or semicountercurrent extraction of the defatted lupin flakes with either 80% ethanol or 80% methanol.