The immunogenicity of a recombinant yeast-derived hepatitis B vaccine was evaluated in a randomized trial involving 80 haemodialysis patients in which three 40 microgram doses were administered according to either a 0, 1, 2 month, or a 0, 1, 6 month vaccination schedule. The vaccine induced an anti-HBs seroconversion in 54% of patients who received the three doses at intervals of one month (Group A) and in 55% of those who were vaccinated at months 0, 1, and 6 (Group B). The geometric mean titres (GMT) seven months after the first injection were 37.7 IU/l in Group A and 91 IU/l in Group B. The seroconversion rate in men (53.6%) was slightly lower than in women (60%), and the respective GMTs were 33.3 and 78.5 IU/l. An age-dependent effect was noted in the anti-HBs response, but the type of renal disease and length of time on dialysis did not influence the antibody response. A 0, 1, and 2 month vaccination schedule seems preferable for haemodialysis patients as it induces more rapid protection.