Lipopolysaccharides are amphiphilic macromolecules indispensable for the growth and the survival of Gram-negative bacteria, one of the most diffuse classes of pathogenic bacteria. LPS are composed of a hydrophilic heteropolysaccharide unit covalently linked to a lipophilic moiety called lipid A, which is embedded in the outer leaflet and anchors these macromolecules to the lipid membrane. Recent studies have revealed that presumably the physical characteristics of these molecules are correlated to their biological activity. Here we suggest a structural study on the architecture and the conformation assumed by these molecules in the lipid membrane.