The study deals with evaluation of ligand specificities of hemoagglutinins and hemolysins of hemolymph of three species of gastropods (Planorbius corneus, Lymnaea stagnalis, and Achatina fulica) and one species of bivalve molluscs (Anodonta cygnea). The hemoagglutinin titer was estimated from hemoagglutination reaction, the hemolysin titer, spectrophotometrically, from release of hemoglobin from sheep erythrocytes. The ligand specificity of hemoagglutinins and hemolysins was evaluated by an inhibitory modification of the hemoagglutination reaction. It has been shown that hemoagglutinins and hemolysins of pulmonary gastropod molluscs have different spectra of ligand specificity to the substances of the carbohydrate nature. Hemoagglutinins and hemolysins of the bivalve mollusc Anodonta cygnea have the same spectrum of ligand specificity. Among the ligands of these lectins, terminal N-acetylated sugars and monosaccharides predominate. Components of bacterial cell walls, lipopolysaccharide and phosphorylcholine, have been revealed among specific ligands of hemolymph hemoagglutinins and hemolysins.