Three endo-β-1, 4-glucanases (CMCases E-I, E-II and E-III) from Bacillus sp. KSM-522 were purified to homogeneity by repeated chromatography on DEAE Bio-Gel A. The molecular weights were 78, 000 for E-I, and 61, 000 for both E-II and E-III, as judged on sodium dodecyl sulfate polyacrylamide gel electrophoresis. The optimum pH values for activity and isoelectric points were around 6 and 4.4 for E-I, and 7-10 and 3.5 for both E-II and E-III, respectively. These CMCases hydrolyzed CMC in a similar random fashion. The alkaline CMCases, E-II and E-III, were not distinguishable from each other with respect to temperature-activity curves, temperature-stability curves, substrate specificity, patterns of action on cellooligosaccharides, susceptibility to inhibitors or effects of metal ions.