A yellow-pigmented, Gram-negative, aerobic, rod-shaped bacterium, strain KIS3-4T, was isolated from soil collected on Daechung Island in the West Sea of Korea. Phylogenetic analysis based on the 16S rRNA gene sequence placed strain KIS3-4T in a distinct lineage in the family Xanthomonadaceae. Strain KIS3-4T shared 87.3-93.7% sequence similarity with members of the family Xanthomonadaceae, and was related most closely to the genera Dyella and Dokdonella. In its biochemical characteristics, strain KIS3-4T was clearly separable from other genera within the family Xanthomonadaceae on the basis of the hydrolysis of cellulose and urea, high G+C content (64 mol%) and fatty acid profile. Major fatty acids (>10% of the total fatty acids) were iso-C17:1omega9c (32.8%), iso-C17:0 (18.0%) and iso-C16:0 (12.7%). Q-8 was the predominant respiratory quinone. Phosphatidylethanolamine and several unidentified aminophospholipids and phospholipids were present. Based on its unique phenotypic, genotypic and phylogenetic features, strain KIS3-4T represents a novel genus and species, for which the name Rudaea cellulosilytica gen. nov., sp. nov. is proposed. The type strain of Rudaea cellulosilytica is KIS3-4T (=KACC 12734T=JCM 15422T).