A Gram-reaction-negative, heterotrophic, marine bacterium, designated strain SPT1T, was isolated from an aged seawater sample which was collected from the shallow coastal region of Nanya, Keelung, Taiwan and stored at room temperature for more than 7 years. Strain SPT1T was a motile rod which exhibited monotrichous flagellation. It required NaCl for growth and exhibited optimal growth at 30-35 �XC, 1-3 % NaCl and pH 7-8. The strain was a strictly aerobic bacterium, incapable of anaerobic growth by nitrate reduction or denitrification, or by fermenting glucose or other carbohydrates. Cellular fatty acids were dominated by C16 : 1�s7c and/or C16 : 1�s6c (23.4 %), C17 : 1�s8c (18.1 %), C16 : 0 (8.5 %), C18 : 1�s7c (8.4 %) and C10 : 0 3-OH (6.3 %). The predominant isoprenoid quinone was Q-8. Polar lipids consisted of phosphatidylethanolamine, phosphatidylglycerol and phosphatidic acid. The DNA G+C content was 57.9 mol%. Phylogeny based on 16S rRNA gene sequences showed that strain SPT1T formed a distinct species-level lineage within the genus Spongiibacter of the class Gammaproteobacteria and shared sequence similarities of 94.4-96.2 % with Spongiibacter marinusand Spongiibacter tropicus, the only two species of the genus Spongiibacterwith validly published names. The 16S rRNA gene sequence similarities between strain SPT1T and other species were less than 93.1 %. Polyphasic taxonomic data obtained in this study indicated that strain SPT1T could be classified as a novel species of the genus Spongiibacter, for which the name Spongiibacter taiwanensis sp. nov. is proposed. The type strain is SPT1T (=JCM 31012T=BCRC 80916T).