Two standard strains of Helicobacter pylori, grown on solid or in liquid medium, were studied for their binding to sialic acid-containing glycosphingolipids on thin-layer plates. NCTC 11637, but not strain 11638, bound to mixtures of gangliosides of various human and animal origins with similar binding patterns and also to polyglycosylceramides of human erythrocytes, leukocytes, and placenta. There was an apparent specificity for NeuAc alpha3Gal of the neolacto series of gangliosides, since NeuAc alpha6Gal or ganglio-series gangliosides did not bind.