Immunization of non-pregnant women in rural Bangladesh with two doses of aluminium-adsorbed tetanus-diphtheria toxoids reduced neonatal mortality by one-third during a period of 9-32 months after vaccination. The reduction in mortality rate was attributable almost entirely to a 75% lower mortality rate among 4-14-day-old infants, when tetanus was the predominant cause of death.In the period up to 20 months following vaccination, the reduction in deaths among 4-14-day-old infants after a single dose of tetanus-diptheria toxoids was about the same as that after two doses. However, beyond 20 months a single dose did not appear to provide protection.