The antibody response in hemodialysis patients was studied after one double dose of influenza vaccine versus one conventional dose plus a booster dose five weeks later. The influenza virus subtype specific IgA and IgG responses were recorded by means of an indirect immunofluorescence assay over a period of 20 weeks. Higher antibody titers, higher response rates and a higher rate of development of protective titers after the single double-dose vaccine indicated it was superior to the single dose/booster dose regimen. It is therefore suggested that hemodialysis patients are immunized with a higher dosage of influenza vaccine to achieve better protection rates.