Host responses to hepatitis B infection were studied in 222 patients in a chronic hemodialysis unit. From 1970 to 1976, patients were monitored monthly for development of hepatitis B surface antigen (HBsAg), antibody to hepatitis B surface antigen (anti-HBs), and serum transaminase (SGPT) elevations. Five categories of patients were identified as: 1) chronic carriers of HBsAg; 2) transiently HBsAg(+), who developed anti-HBs; 3) HBsAg(-) on admission, who developed anti-HBs without becoming HBsAg(+); 4) anti-HBs(+) on admission; 5) uninfected who remained HBsAg(-) and anti-HBs(-). For a patient who became HBsAg(+) in this clinic, the probability of becoming a chronic carrier was 62-8% and rose to 88.5% if he or she had been HBsAg(+) for five consecutive months. Males were more likely to become chronic carriers, and females were more likely to develop anti-HBs. Neither age, race, nor type of underlying kidney disease was associated with particular host responses to hepatitis B virus. No effect of hepatitis B infection on mortality was detected. Variation in host response to hepatitis B infection among renal dialysis patients may affect the usefulness of hepatitis B hyperimmune globulin and hepatitis B vaccine and be related to the outcome of kidney transplantation.