The aim of this study was to assess antihemagglutinin and antineuraminidase antibody kinetics in 26 patients with renal diseases vaccinated against influenza in two consecutive epidemic seasons. Antibody responses were measured before immunization and 1, 3 and 6 months after immunization. Antihemagglutinin (HI) antibodies were determined by the hemagglutinin inhibition test and antineuraminidase (NI) antibody levels by the neuraminidase inhibition test. After vaccination HI and NI antibody titers significantly increased when compared with the pre-vaccination levels. Three months after vaccination the protection rates ranged from 50 to 61.5% in the 1995/96 season and 100% for all antigens in the 1996/97 season. Response rates ranged from 50 to 57.7% and 93.8 to 100% respectively. Significantly higher humoral response was recorded in the 1996/97 season than in the 1995/96 season. No serious adverse reactions were observed in the vaccinated patients and no symptoms of influenza or influenza-like infection were noted. In spite of some doubts about the safety and efficacy of influenza vaccination in patients from high-risk groups, the results of this study showed that many of them are able to produce HI antibodies in titers which are sufficient to protect against the influenza infection.