The lysozyme catalyzed transglycosylation with glycol chitin or related oligosaccharides as substrate and p-nitrophenyl β-glycoside of 2-acetamido-2-deoxy-D-glucopyranoside as acceptor was studied in order to obtain basic information which is expected to be available for the elucidation of the mechanism of lysozyme catalyzed reaction. In the present experiments, the general features of the transglycosylation, the effects of additives, the total transglycosylation by gel-filtration method and the abilities of several sugars as acceptor were examined and the exact comparison between the hydrolysis and the transglycosylation was made. Some subjects related to the mechanism of lysozyme catalysis were also discussed briefly.