Antibodies protect against disease caused by viruses that infect the lower respiratory tract, and contribute to the resolution of established infection by these pathogens. The kinetics and specificities of antibodies secreted in response to respiratory virus infections are described, however the mechanisms by which antibodies prevent or resolve infection are less clear Recent studies of virus neutralization in cell culture, the immunobiology of respiratory virus infections in animal models, and passive immunoprophylaxis of human patients are beginning to better define the role of antibodies in immunity to respiratory viruses.