Two novel bacterial strains, designated CJ20^T and CJ99^T, belonging to the genus Sphingomonas, were isolated from the Han River in South Korea and a wetland in South Korea, respectively. Cells of both strains were Gram-stain-negative, aerobic, non-motile and yellow-pigmented. Strains were shown to grow optimally at 30˚C and pH 7 in the absence of NaCl on tryptic soy medium. Phylogenetic analysis based on 16S rRNA gene sequences showed that strains CJ20^T and CJ99^T belonged to the genus Sphingomonas and were most closely related to S. asaccharolytica Y-345^T and Sphingomonas koreensis JSS26^T with 97.87% and 97.58% 16S rRNA gene sequence similarities, respectively. Average nucleotide identity and digital DNA-DNA hybridization values of strain CJ20^T with S. asaccharolytica Y-345^T were 74.1% and 15.9%, respectively and those values of strain CJ99^T with S. koreensis JSS26^T were 73.9% and 15.6%, respectively. Both strains contained ubiquinone (Q-10) as the predominant respiratory quinone. The major polar lipids of strains CJ20^T and CJ99^T comprised phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol, and sphingoglycolipid. The predominant fatty acids of both strains were summed feature 8 (C_18:1 ω7c and/or C_18:1 ω6c) and C_16:0. Based on polyphasic taxonomic analyses, strains CJ20^T and CJ99^T represent novel species of the genus Sphingomonas, for which names Sphingomonas degradans sp. nov. and Sphingomonas paludis are proposed, respectively. The type strains are CJ20^T (= KACC 23909 = JCM 37720) and CJ99^T (= KACC 24077 = JCM 37956).