A bacterial strain, designated SW-3(T), was isolated from the reef-building coral Isopora palifera, from Southern Taiwan, and was characterized by using a polyphasic taxonomic approach. Cells of strain SW-3(T) were Gram-reaction-negative, aerobic, rod-shaped and motile by means of monopolar flagella and formed cream-white colonies. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain SW-3(T) belonged to the genus Paracoccus and its most closely related neighbours were P. aestuarii B7(T), P. homiensis DD-R11(T), P. marinus KKL-A5(T), P. denitrificans DSM 413(T) and P. zeaxanthinifaciens R-1512(T), with sequence similarities of 96.8, 96.6, 96.1, 95.8 and 94.9 %, respectively. Strain SW-3(T) exhibited optimal growth at 25-30 �XC and pH 9-10 and in 3-5 % (w/v) NaCl. The predominant cellular fatty acid was summed feature 8 (C(18 : 1)�s7c and/or C(18 : 1)�s6c; 75 %). The major respiratory quinone was Q-10. The polar lipid profile consisted of a mixture of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine and several uncharacterized polar lipids. The DNA G+C content of strain SW-3(T) was 63.7 mol%. The results of physiological and biochemical tests allowed clear phenotypic differentiation of this isolate from recognized species of the genus Paracoccus. It is evident from the genotypic, phenotypic and chemotaxonomic data that strain SW-3(T) represents a novel species of the genus Paracoccus, for which the name Paracoccus isoporae sp. nov. is proposed. The type strain is SW-3(T) (= LMG 25205(T) = BCRC 17967(T)).