The antibody and cell-mediated immune responses after influenza vaccination were compared in 33 patients with chronic bronchitis and in 40 hemodialyzed patients. The results suggest a moderate impaired response in the hemodialyzed patients since the antibody titers and the level of cell-mediated immunity were consistently lower in these patients as compared to those suffering from chronic bronchitis. Nevertheless, the vaccine elicited an immune response in all the pre-vaccine seronegative dialyzed patients.