The structure of glucose oligomers obtained by sonochemical glucose polymerization in dodecanol under Fischer glycosylation conditions was investigated. Oligomers having a degree of polymerization up to 23 were observed, with a mean value higher for the sonocatalyzed reaction compared to classical heating, as revealed by mass spectroscopy using the MALDI-TOF technique. The presence of anhydro terminal units was also ascertained by this method. Glycosidic bond types and branching ratios were evaluated after chemical degradation of the oligomers.