To investigate the symbiotic roles of the gut microbiota in the fungus-growing termite Macrotermes barneyi, a novel strain with chitinolytic and cellulolytic activity, designated strain an-chi-1T, was isolated from the hindgut of M. barneyi. Strain an-chi-1T grows optimally at 28-30 °C, pH 8.0 in PYG medium. On the basis of 16S rRNA gene sequence analysis, this isolate belongs to the genus Cellulomonas with high sequence similarity to Cellulomonas iranensis (99.4%), followed by Cellulomonas flavigena (98.4%), Cellulomonas phragmiteti (97.4%), Cellulomonas oligotrophica (97.2%) and Cellulomonas terrae (97.0%). The DNA-DNA relatedness between an-chi-1T and the type strains of C. iranensis and C. flavigena DSM20109T are 35.4% and 23.7%, respectively. The major cellular fatty acids are anteiso-C15:0 and C14:0. The polar lipid profile consists of diphosphatidylglycerol, phosphatidylinositol mannosides, phosphatidylinositol dimannosides and one unidentified phospholipid. The cell-wall sugar is ribose. The peptidoglycan contains glutamic acid, aspartic acid and alanine. The DNA G+C content is 67.3 mol%. Based on its distinctive phenotypic, phylogenetic, and chemotaxonomic characteristics, an-chi-1T represents a novel species of the genus Cellulomonas, for which the name Cellulomonas macrotermitis sp. nov. is proposed. The type strain is an-chi-1T (= JCM 31923T = CICC 24195T).