Three groups of healthy teenage New Zealand children were given 2.5 micrograms, 5 micrograms and 10 micrograms, which is the currently recommended dose, of Merck Sharp and Dohme recombinant yeast-derived hepatitis B vaccine at time 0, 1 and 6 months and tested for antibody responses to vaccine and for other hepatitis B virus markers. Seroconversion rates exceeded 98% in all three groups. Geometric mean titres (GMT) of the anti-HBs increased with higher doses. There was no significant differences in GMT between the sexes. Under the conditions of this study, 2.5 micrograms doses of this vaccine induced an excellent antibody response in children 12-14 years of age.