A lipoprotein concentrate was obtained by extraction from sunflower seeds with a water-ethanol-salt solution. This contained about 50% protein and 20% fat. Chemical score was 51, based on analysis of available lysine. For a 3-week period the protein efficiency ratio (PER) was 2.16 and the productive protein value (PPV) 37.6. After addition of lysine the PER increased to about 3.3 and the PPV to about 58. A 90-day toxicological study was carried out on rats fed a diet containing 11 % protein from the lipoprotein concentrate as the sole source of protein. Histological examinations showed a testicular atrophy but otherwise mainly normal conditions. Hematological findings were normal.