The response to recombinant hepatitis B vaccine was assessed in 31 seronegative infants (2-26 months old) with protein calorie malnutrition (PCM), compared with 13 seronegative age- and sex-matched healthy infants. Both groups received three 10 micrograms vaccine doses at 0, 1, and 6 months. At month 8, all healthy infants and 87 per cent (27 out of 31) of PCM infants were seroprotected. Thus, hepatitis B vaccination (Engerix-B, SmithKline Beecham Biologicals) can be used effectively in PCM for mass vaccination in developing communities.