Neonatal and maternal tetanus infections remain an important cause of death in many countries. Few studies have reported tetanus toxoid antibody levels of adolescent girls. As part of the Expanded Programme on Immunization most girls receive up to 3 injections in early childhood, and many subsequently do not receive booster vaccinations until pregnant. We determined (by ELISA) tetanus antibody seropositivity in adolescent girls from Malawi (in 1996), Nigeria (in 1993) and Pakistan (in 1996), and response to tetanus vaccination in adolescent girls from Pakistan. Geometric mean titres (GMT, IUlmL) were 0.94 in 117 Malawian, 0.32 in 154 Nigerian and 1.08 in 162 Pakistani girls. In Nigeria, 54.7% of adolescents were seronegative, of whom 26.8% had a history of unsafe abortion. In Malawi and Pakistan all girls were seropositive and in Pakistan, following a booster vaccination, titres increased 3-fold, with a lower response in older girls. The results indicated that adequate childhood immunization is likely to provide protective levels through adolescence. Booster vaccination in late childhood/early adolescence should protect the majority of women throughout their reproductive lives. This practice would reduce the risks of girls exposed to infection through unsafe abortions, and may be the best option for countries seeking to improve their vaccination schedule, especially where tetanus vaccine coverage in pregnant women is unacceptably low.