Purpose: The purpose of this study was to assess the prevalence of traumatic dental injuries (TDIs) in the primary dentition that presented to the emergency department (ED) of a level-one trauma center at a children's teaching hospital. Methods: Electronic health records of 1,170 patients with 2,746 traumatic dental injuries who presented to the ED over a 55-month period were reviewed in this retrospective cohort study. A subset of these (541 patients) with multiple injuries in primary teeth were examined. Results: The prevalence of primary tooth injury was 41 percent (1,120 out of 2,746). Most injuries were sustained by males (N equals 311; 57 percent); lateral luxations (N equals 341; 30 percent) were the most common injuries to the primary dentition. The primary maxillary central incisors were the most common teeth to be injured. Concomitant injuries were reported in 50 (4.5 percent) primary teeth. Conclusions: Traumatic dental injuries occurred frequently in the primary dentition, with lateral luxations being reported most often. Over 40 percent of all reported TDIs occurred in the primary dentition. Emergency room providers should be prepared to manage primary tooth TDIs.