The study was done to isolate Concanavalin A from jack bean (canavalia ensiformis).The protein was purified by using affinity chromatography. The activity of the lectins was determined by haemagglutinin assay and the purity of the protein was tested by Sodium dodecyl sulphate Polyacrylamide Gel Electrophoresis (SDS-PAGE). The activity of lectins is quantified by their ability to agglutinate erythrocyte. The eluted protein exhibited agglutinating activity when reacted against different types of fresh erythrocytes. In SDS-PAGE in affinity bands was observed of 104 kDa. It is a homotetramer, each subunit bind with metallic atom (Mn2+ and Ca2+).