A novel hemagglutinin produced by insect pathogen Beauveria bassiana was isolated from mycelium of the stationary growing microorganism and purified by adsorption on carboxymethyl cellulose followed by separation on Spherogel TSK--phenyl 5 PW column using high performance liquid chromatography. The purified hemagglutinin was homogeneous in polyacrylamide gel electrophoresis and isoelectric focusing. Its molecular weight was estimated to be around 25,000, isoelectric point was found at pH 8.6 +/- 0.2. Amino acid composition of purified B. bassiana hemagglutinin was determined by HPLC fluorometric analysis of o-phthaldialdehyde derivatives of protein hydrolysate. Purified hemagglutinin agglutinated some animal and all human erythrocytes independently of blood group ABO phenotype. The observed hemagglutination is not inhibited by glucose/mannose, N-acetylglucosamine, N-acetyl galactosamine, galactose, L-fucose and sialic acid.