The Maasai have high rates of death from neonatal tetanus, partly due to their custom of packing the umbilical stump with cow dung. We report on the effect of a simple health promotion programme, designed in consultation with the local community and carried out by local women. After introduction of the programme in 1981, neonatal (<6 weeks of age) tetanus rates fell sharply, and by 1988 annual death rates had dropped to 0.75 (range 0-3) per 1000 births in the intervention areas compared with 82 (74-93) per 1000 in control areas.