The goal of the present study was to identify the factors related to the occurrence of dental trauma in deciduous teeth. Over a period of 25 months, 85 children between 10 months and 6 years of age were assisted by the staff of the Pediatric Dentistry Clinic of the Federal University of Santa Catarina (UFSC) Florianópolis, Brazil. The children, all assisted by only one professional, a dentist working as a trainee in the Pediatric Dentistry Clinic, had 157 traumatized teeth treated. The occurrence of trauma was higher in male patients (51.8%) and in children between 1 and 3 years old. The average age was about =2.7 years. The 54.1% of the assisted children had more than one traumatized tooth and the repeat trauma occurred 16.7% of the time. Anterior teeth represented 98.7% of the cases and 76.4% of the trauma were on the maxillary central incisor teeth. Both sides of the mouth had approximately the same number of traumatic injuries. Luxations were more frequent (85.4%) than fractures (14.6%). Subluxations represented 38.8% of the luxated teeth. Falls were the main cause of trauma (78%). A percentage of 41.9 children were assisted by a dental professional during the first 24h after the incident. The study concluded that the deciduous dentition is mostly affected by luxations (subluxations) that occur specially on the maxillary central incisor teeth, in patients between 1 and 3 years of age. Falls are the most common etiological factor and more than one traumatized tooth is common. Some of the cases were repeat traumatic injuries.