Abstract: The present invention relates to novel aminooligosaccharide derivative and pharmaceutically acceptable non-toxic salts thereof, which possess potent saccharide hydrolase inhibition and antibacterial activities. The invention also relates to a process for preparing the same and to pharmaceutical compositions containing the same as active ingredients. In accordance with the present invention, the inventors isolated novel aminooligosaccharide derivative from a soil microorganism categorized as Streptomyces sp., and discovered that it can be applied as potent inhibitors for saccharide hydrolases and antibacterial agents as well.