Structural analysis of the 3-deoxy-D-manno-2-octulosonic acid (Kdo) region in a lipopolysaccharide (LPS) II isolated from Coxiella burnetii strain Nine Mile in avirulent phase II revealed the presence of three variously linked Kdo residues. The lipid A proximal Kdo is substituted at C-4 by a Kdo-(2-->4)-Kdo disaccharide and this structural arrangement of the Kdo residues is similar to that of enterobacterial LPSs.