A psychrophilic, Gram-negative bacterium, designated MOL-1^T, was isolated from water of Lake Michigan. 16S rRNA gene sequence analysis revealed that the sequence of strain MOL-1^T has sequence similarity of 95.6, 94.8, 94.3, 94.3, 94.2 and 93.9 %, respectively, to the 16S rRNA gene sequences of Sphingobacterium shayense HS39^T, S. lactis WCC 4512^T, S. composti T5-12^T, S. daejeonense TR6-04^T, S. bambusae IBFC2009^T and S. alimentarium WCC 4521^T. The major cellular fatty acids were iso-C_{15 : 0}, iso-C_{17 : 0} 3-OH and summed feature 3 (iso-C_{15 : 0} 2-OH and/or C_{16 : 1}ω7c). Menaquinone MK-7 is the predominant respiratory quinone, while sym-homospermidine is the predominant polyamine. The polar lipid profile is composed of the predominant lipids phosphatidylethanolamine and unidentified polar lipid L2, with moderate amounts of unidentified polar lipids L1, L5 and L6 and unidentified aminophospholipids APL1 and APL2 and minor to trace amounts of unidentified polar lipids L3, L4, L7, L8, L9 and L10, unidentified phospholipid PL4 and unidentified aminophospholipid APL3. After molecular and phenotypic studies, including chemotaxonomic analyses, it was concluded that strain MOL-1^T represents a novel Sphingobacterium species, for which the name Sphingobacterium psychroaquaticum sp. nov. is proposed. The type strain is MOL-1^T ( = NRRL B-59232^T = DSM 22418^T).