The liver of a gastropod, Turbo cornutus contained α-N-acetylglucos-aminidase, β-N-acetylglucosaminidase [EC 3.2.1.30], α-N-acetylgalactos-aminidase and βN-acetylgalactosaminidase. The optimum pH value of the all four enzymes was near 4.0. Sephadex G-200 column chromato-graphy and heat treatment showed that α-N-acetylglucosaminidase, β-N-acetylglucosaminidase and α-N-acetylgalactosaminidase were different enzymes. β-N-Acetylglucosaminidase and β-N-acetylgalactosaminidase were not separated from each other by the above procedures, and the identity of the two enzymes was demonstrated kinetically. α-N-Acetylglucosaminidase from Turbo cornutus was purified 76-fold with a recovery of 24%. The purified enzyme preparation contained small amounts of β-N-acetylglucosaminidase, β-glucosidase [EC 3.2.1.21] and α-galactosidase [EC 3.2.1.22], but was practically free from other glycosidases. The enzyme was activated by sodium chloride and inhibited by PCMB. β-N-Acetylglucosaminidase from Turbo cornutus was purified 16-fold. The purified enzyme was practically free from all other glycosidase activities except that of β-N-acetylgalactosaminidase. The enzyme was activated by sodium chloride and inhibited by acetate. It released 2.7 moles ofN-acetylglucosamine per mole of ovomucoid, without any release of hexose.