The purpose of this work was the isolation and characterization of grain protein from five Venezuelan Genotypes (U-02, Yaracuy, Valle De La Pascua, Originally Tovar) of Jack Bean (Canavalia ensiformis). The average protein content from these genotypes was 31.37%, it ranged between 28.44% and 33.05%. The protein isolation was performed by solubility extraction procedures, showed: 84.57% of albumins, globulins and non proteic nitrogen and 15.43% of alcohol insoluble reduced glutelin (AIG). The content of anti-nutritional factors (canavanine and hemagglutination title) found in protein fractions were respectively: Albumins 1.96%, +4; globulins 0.17%, +5 and AIG 0.22%, +1. It was observed that protein fractions of genotype Tovar had the lowest canavanine values (0.79%, 0.02% and 0.00% respectively). The globulins gave the highest in vitro protein digestibility (65.20%) followed by Albumins (58.90%) and AIG (37.28%).