This questionnaire-based study investigated the traumatic background and trauma-related symptomatology among 141 treatment-seeking individuals with high levels of dental anxiety and among a low-anxious reference group consisting of 99 regular dental patients. The highly anxious individuals reported a significantly higher number of traumatic events, both within and outside the dental or medical setting, than those in the reference group (73% vs. 21%). Horrific experiences in the dental setting were the most common traumatic events reported. Of the highly anxious individuals, 46.1% indicated suffering from one or more of the post-traumatic stress disorder (PTSD) symptom clusters (re-experiencing, avoidance, loss of interest, and insomnia), while in the reference group this percentage was 6%. Severity of dental anxiety was significantly associated with number of screening criteria for specific phobia and the extent to which the anxious subjects displayed symptoms of post-traumatic stress. Two variables were uniquely predictive for positive diagnostic screens for dental phobia and PTSD: having experienced a horrific dental treatment and having been a victim of a violent crime. In conclusion, post-traumatic symptoms are common accompaniments of severe forms of dental anxiety and are experienced even when dental treatment is not imminent.