Aim: The aim of the present study was to identify some factors related to the occurrence of dental trauma in mixed and permanent dentition. Design of the study: Over a period of two months 1325, 6 to 18 year olds from three primary schools in Valencia were examined. Data was collected through clinical examinations and interviews and their Dental trauma was classified according to IADT´s criteria. Results: The prevalence of dental injuries was 6%; boys aged between 12-18 years old experienced more injuries than girls. There was a statistical difference between the types of fractures. Non complicated coronal fractures were the most frequent (9.18%). Games were the main cause of trauma (40%) in both sexes. In 14.3% of patients a dental colour change was observed. Angle´s class I was the most frequent in traumatized injured children (41.2%). Conclusions: The present study revealed a relatively low prevalence of dental trauma, but this figure still represents a large number of children. Therefore, educational programs are to be initiated for the community regarding causes , prevention and treatments of traumatic dental injuries.