The aim of this study was to evaluate etiology, types of traumatic dental injuries, treatment and to determine the incidence of complications according to dental injuries in patients who referred to Yeditepe University, Faculty of Dentistry, Istanbul, Turkey. The study was based on the clinical data of the 161 traumatized teeth in 92 patients. WHO classification slightly modified by Andreasen & Andreasen for dental trauma was used. The causes and localization of trauma, traumatized teeth classification, treatment and complications were evaluated both primary and permanent teeth. The distribution of complications according to diagnosis and treatment of the injured teeth were evaluated. Of 35 (38%) girls and 56 (72%) boys with a mean age 7.6 +/- 3.5 (ranging 1-14.2) participated to study and the mean followed up was 1.72 +/- 1.28 years (ranging 0.10-3.8 years). From the 161 affected teeth, 69 (42.9%) were in primary teeth and 92 (57.1%) in permanent teeth. The highest frequency of trauma occurred in the 6-12 year age group. Overall boys significantly outnumbered girls by approximately 1:1.6. The most common type of injury in the primary and permanent teeth was seen as luxation (38%) and enamel fracture (20%) of the maxillary central incisors, respectively. Falls were the major sources of trauma both the primary (90%) and the permanent teeth (84%). In the primary dentition, the most common type of soft tissue injury is contusion (62.5%) and in the permanent dentition, it is laceration (49%). The most of the treatment choice was determined as examination only and extraction in primary teeth (58 and 24.6%, respectively) while it was applied as restoration and pulpectomy in permanent teeth (31.5 and 18.5%, respectively). Complications were recorded on 37 teeth (23%) with a most common type of necrosis (10.5%) and dental abscess (7.4%). Necrosis was more frequent in luxation whereas dental abscess were in crown fracture with pulpal involvement in both dentitions. The study showed that boys were more prone to dental traumas than girls. Falls were more frequent trauma type with a high complication risk. It reveals that the time of the immediate treatment showed the important predisposing factors that increase the success of treatment and decrease the risk of complication. The correct diagnosis of dental injuries is more important for eliminating the occurrence of complications.