The aim of this study was to investigate the prevalence of teeth with untreated dental trauma among children aged 4-15 years in Dar es Salaam, Tanzania. A sample of 4524 children from three districts of different socio-economic status in the Dar es Salaam area was examined for signs of dental trauma in 1998/99. In 21% of all children examined, at least one type of untreated dental trauma was observed. A high percentage of untreated dental trauma was observed at the ages of 4 and 15 years. The most frequently observed type of dental trauma was enamel fracture (67%) followed by enamel-dentin fracture (26%). A significant gender influence on the occurrence of untreated dental trauma was observed, with more boys (23%) having untreated dental trauma than girls (19%). A higher percentage of untreated dental traumas was observed among children in the district with highest SES (26%) compared to the prevalence in the other two districts (14-17%). The findings of this study show that dental traumas are prevalent among Tanzanian children. Therefore, provision of information to the lay community about the importance of early management of dental trauma, ways of preventing trauma and appropriate handling of avulsed teeth is essential in order to minimize the rate of dental injuries and the related complications.