Abstract Sialic acid has long been considered the sole cellular receptor for influenza viruses, but it has been demonstrated that influenza can infect cells independently of surface sialic acid [Glycobiology 10 (2000) 649]. Here, we evaluate possible alternative influenza virus receptors, and find evidence for specific virus-binding-proteins in vitro and mediation of entry by carbohydrates containing terminal α- N -acetylgalactosamine. Characterization of such receptors may lead to identification of alternative targets for the design of anti-influenza drugs.