Lupin is a promising protein source with a high protein concentration. Breeding efforts have resulted in the development of varieties low in quinolizidine alkaloids. The objective of this work was to evaluate 22 different blue lupin genotypes for a high protein concentration and low content of antinutritional alkaloids. These genotypes were grown under uniform controlled environmental and soil conditions, and the harvested seeds were evaluated for their composition. The low phosphorus content confirmed that the phytic acid presence was low in lupin, especially compared to other legumes. Furthermore, some of the varieties had less than 200 ppm alkaloids. Lupin proteins were rich in leucine and lysine, with the lowest amino acid concentration being methionine. There were significant differences in the protein concentration and recovery. This work demonstrated that an approach for selection of genotypes should be based on not only agronomic yields but also nutritional phenotypes, driving better decision making on future varietal selection.