An aerobic, Gram-negative bacterial strain, designated KU27E1(T), which degrades phthalate and dimethylphthalate, was isolated from seawater obtained from the coastal region of Ishigaki Island, Japan. Cells are motile rods with polar flagella. Strain KU27E1(T) grew at 15-30A degrees C, pH 6.0-8.0, in the presence of 1.0-2.0% (w/v) NaCl. The 16S rRNA gene sequence analysis revealed that this strain was affiliated with the family Rhodobacteraceae in the class Alphaproteobacteria, and was most closely related to Tropicibacter naphthalenivorans (96.8%). The predominant respiratory lipoquinone was ubiquinone-10, and the major cellular fatty acid was C-18:1 omega 7c (88.5%). The G+C content of genomic DNA was 58.7 mol%. Based on the physiological, chemotaxonomic, and phylogenetic data, strain KU27E1(T) is suggested to represent a novel species of the genus Tropicibacter, for which the name Tropicibacter phthalicus sp. nov. is proposed. The type strain of Tropicibacter phthalicus is designated as KU27E1(T) (=JCM 17793(T) = KCTC 23703(T)).