Three stains of cellulose-degrading, aerobic, mesophilic bacteria were isolated from forest soils and, from their cultural, biochemical, and physiological characteristics, they were identified as members of the genusCellulomonas. Unusual biochemical characteristics, e.g. urea hydrolysis, were observed in two isolates. These characteristics have not previously been reported for cellulomonads and may prove to be significant for characterization ofCellulomonas spp. The isolates were able to use urea as a N source in cellulose fermentation. All three strains were motile, with one to four peritrichous flagella observed. Amino acid and polysaccharide composition of the cell walls of the three isolates were identical.