SummaryGroups of atopic and non‐atopic individuals were immunized intranasally with fluid tetanus toxoid, an antigen which normally does not gain access to the nasal cavity. Anti‐tetanus toxoid antibody response was evaluated in nasal wash, sputum and serum specimens by passive haemagglutination.Titres were high in serum and low in exocrine fluids throughout the course of immunization. Mean nasal wash titres rose to a significantly higher level in the normal than in the atopic group. Twelve of twenty normal subjects responded with a greater than three‐fold rise in nasal antibody as opposed to one of nineteen atopic individuals. Exocrine anti‐toxoid haemagglutinating activity was inhibited by anti‐IgA but not by anti‐IgM or IgE, suggesting that the bulk of secretory antib