The novel monosaccharide 8-amino-3,8-dideoxyoct-2-ulosonic acid (Kdo8N) was isolated by methanolysis from the lipooligosaccharide of the marine Gram-negative bacterium Shewanella pacifica. After HPLC purification, the absolute configuration was determined by the Mosher ester method and proven to be 4 R,5 R,6 R,7 R. This established the d- manno- configuration of the monosaccharide.