Abstract: | The lipopolysaccharide ofYersinia enterocolitica serovar 0:8 (strain 161) isolated from the microbial mass by aqueous-phenol extraction contains residues of L-fucose-6-deoxy-D-gulose, D-mannose, D-galactose, D-glucose, D- and L-glycero-D-mannoheptoses, N-acetyl-D-glucosamine, N-acetyl-D-galactosamine, and 2-keto-3-deoxyoctonic acid (KDO). The polysaccharide was obtained by mild acid hydrolysis of the lipopolysaccharide followed by gel filtration on Sephadex G-50. On the basis of the results of monosaccharide analysis, methylation, Smith degradation, and partial hydrolysis the following structure is suggested for the repeating unit of the O-specific polysaccharide of the LPS ofYersinia enterocolitica, serovar 0:8: |