A novel Gram-negative, strictly aerobic, heterotrophic, non-motile and yellow-pigmented bacterial strain, designated HD4T, was isolated from the sea urchin Hemicentrotus pulcherrimus collected from the Yellow Sea in China. Optimal growth of the strain was observed at 28–30 °C, pH 6.8–7.3, and in the presence of 3–5 % (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequence revealed that strain HD4T exhibited high similarity with the members of Salegentibacter (92.3–95.4 %). The DNA G+C content was 37.0 mol%, MK-6 was the main respiratory quinone and summed feature 3 (comprising iso-C15:0 2-OH/C16:1ω7c), iso-C15:0, iso-C17:0 3-OH and anteiso-C15:0 were the major cellular fatty acids. The predominant polar lipids in strain HD4T were phosphatidylethanolamine and two unknown lipids (L2, L4). Based on the phylogenetic, physiological and biochemical characteristics, strain HD4T should be classified as a novel species within the genus Salegentibacter, for which the name Salegentibacter echinorum sp. nov. is proposed. The type strain is HD4T (=CICC 10466T = NRRL B-59666T).