An agglutinin with a molecular mass of 130 kDa has been isolated from the seeds of Alpinia zerumbet cv.'Variegata'. The isolation procedure involved anion exchange chromatography on DEAE-cellulose, affinity chromatography on Affi-gel blue gel, and gel filtration by fast protein liquid chromatography on Superdex 75. The agglutinin exhibited hemagglutinating activity toward rabbit erythrocytes which could not be inhibited by simple sugars. It was composed of four identical 32-kDa subunits with substantial N-terminal sequence similarity to chitinase and yieldin. The hemagglutinating activity of A. zerumbet agglutinin was stable up to 80(o)C and not affected by presence of a variety of salts. The agglutinin stimulated [methyl-(3)H]-thymidine uptake by mouse splenocytes. It did not exhibit antifungal activity.