Lupinusis a very diverse genus with many species. The aim of this study was to determine the influence of different methods of application of sodium selenite on the nutritional value of white lupine variety Degas. The highest effect on the content of crude protein was obtained by spraying vegetating plants before the beginning of the flowering phase. In this variant, a class 1 grain was obtained while meeting other requirements of the feed lupin quality standard. This study reveals that the use of selenium contributed to increasing the collection of crude protein at the harvest of white lupin. It is assumed that selenium stimulated the processes of nitrogen entering plants and its redistribution from vegetative to generative organs, as well as activated the synthesis of proteins and their accumulation in the grain of white lupin. It was found that the content of alkaloids in the resulting crop of white lupin did not exceed acceptable levels, which allows it to be used for feed purposes and the preparation of various types of feed. The use of selenium contributed to the increase in the collection of crude protein content at the harvest of above-ground plant mass as it stimulates nitrogen processes in plants and its redistribution from vegetative organs to generative organs, as well as the synthesis of protein compounds in the lupin grain.