Agglutinin with hemagglutinating activity was found in hemolymph of Tegillarca granosa Linnaeus. By extraction, fraction with saturated ammonium sulfate precipitation, gel filtration on Sephadex G-100 and followed by affinity chromatography on Sepharose 4B, an agglutinin was purified from the hemolymph of T. granosa. The purified lectin contains 5.02% neutral saccharide. The molecular weights is about 123 KDa, which showed 2 bands on SDS-PAGE, and the relative molecular weights of these subunits were 15 KDa and 16 KDa, respectively. In its amino acid composition, Asp has the highest content, followed by Glu and His, but there is a lack of Met. Assays for erythrocyte agglutination and sugar inhibition were done in microtiter plates. The result indicared that TGL-hemolymph could agglutinate erythrocytes from the natural and enzyme-treated erythrocytes of human and animals, and the highest activity was found in the agglutination with rabbit erythrocytes. The agglutinic activity of TGL-hemolymph was inhibited by lactose and D-galactose. The hemagglutination activity of TGL-hemolymph depended on Ca2+, and it showed the highest hemagglutination activity in pH 7.0. Thermostability was not high. The agglutinating activities changed from 2(5) to 2(1) between 30-70 degrees C, and was completely destroyed beyond 80 degrees C.