In the present study we investigated the humoral response to inactivated subunit influenza vaccine in patients with Wegener's granulomatosis, who were in clinical and serological remission after immunosuppressive treatment (Group I). The results were compared with patients with Wegener's granulomatosis who were treated immunosuppressively, but were not vaccinated (Group II) and with healthy persons who received the vaccine (Group III). After vaccination, antihemagglutinin and antineuraminidase antibody titers significantly increased in Groups I and Group III subjects when compared with the pre-vaccination values. Post-vaccination protection rates ranged from 51.4% to 74.3% in Group I patients and from 65.7% to 94.3% in Group III subjects. In Group II, the protection rates were between 0% and 21.4%. The response rates ranged from 60% to 74.3% in Group I patients and from 71.4% to 88.6% in Group III subjects. In Group II, the response rates were between 7.1% and 21.4%. The study confirmed the immunogenicity of influenza vaccine in patients with Wegener's granulomatosis and showed similar response in the patients to those present in healthy people.