Mucosal delivery of inactivated vaccines that are able to elicit protective immune responses against respiratory diseases has been a long time goal of vaccinologists. Such vaccines would enable a more appropriate means of vaccination against respiratory diseases than those currently delivered by a parenteral route. The intranasal delivery of inactivated influenza vaccine plus the ISCOMATRIX (IMX) adjuvant, simply mixed together, was able to induce serum haemagglutination inhibition (HAI) titres in mice far superior to those obtained with unadjuvanted vaccine delivered subcutaneously. Furthermore, the IMX adjuvanted vaccine delivered intranasally induced mucosal IgA responses in the lung, nasal passages and large intestine, together with high levels of serum IgA. Intranasal delivery of IMX adjuvanted influenza vaccine in sheep gave antibody responses in both serum and nasal secretions that surpassed the levels obtained with unadjuvanted vaccine administered subcutaneously. These observations suggest that it may be possible to induce effective immunity to influenza in humans by intranasal vaccination with an IMX adjuvanted inactivated vaccine.