alpha -D-Mannosyl-maltotriose (Man-G3) were synthesized from methyl alpha -mannoside and maltotriose by the transfer action of cu-mannosidase. (Man-G3)-beta CD and (Man-G3)(2)-beta CD were produced in about 20% and 4% yield, respectively when Aerobacter aerogenes pullulanase (160 units per 1 g of Man-G3) was incubated with the mixture of 1.6 M Man-G3 and 0.16 M beta CD at 50 degreesC for 4 days. The reaction products, (Man-G3)-beta CD were separated to three peaks by HPLC analysis on a YMC-PACK A-323-3 column and (Man-G3)(2)-beta CD were separated to several peaks by HPLC analysis on a Daisopak ODs column. The major product of (ManG3)-beta CDs was identified as 6-O-alpha-(6(3)-O-or-D-mannosyl-maltotriosyl)-beta CD by FAB-MS and NMR spectroscopies. The structures of (Man-G3)(2)-beta CDs were analyzed by TOF-MS and NMR spectroscopies, and confirmed by comparison of elution profiles of their hydrolyzates by at-mannosidase and glucoamylase on a graphitized carbon column with those of the authentic di-glucosyl-beta CDs The structures of three main components of (Man-G3)(2)-beta CDs were identified as 6(1),6(2)-, 6(1),6(3)- and 6(1),6(4)-di-O-(6(3)-O-alpha -D-mannosyl-maltotriosyl)-beta CD.