α- And β-glucoside derivatives of validamine and valienamine were prepared by enzymatic transglucosidation using α- and β-glucosidase of rhodotorula lactosa. The structures of these derivatives have been elucidated by 13C- and 1H-nuclear magnetic resonance spectral analysis. Thus, 7-α-glucoside, 7-α-isomaltoside, and 4-α-glucoside of validamine and 7-α-glucoside, 7-α-isomaltoside, 4-α-glucoside, and 4-α-isomaltoside of valienamine were obtained from maltose and validamine or valienamine using α-glucosidase. 7-β-Glucoside, 2-β-glucoside, and 4-β-glucoside of validamine or valienamine were obtained from cellobiose and validamine or valienamine using β-glucosidase. These derivatives were tested for α-glucosidase inhibitory activity on rat small intestinal glycosidases.