Exposure to violence from patients or relatives causes problems in emergency departments. To assess the development of posttraumatic symptoms in pre-hospital emergency care professionals assaulted by patients and/or relatives, it may be crucial to establish preventive measures at different levels. This study examined 358 pre-hospital emergency care professionals assaulted by patients and/or relatives. The aims of the present study were (a) to assess the presence of posttraumatic symptoms and posttraumatic stress disorder (PTSD) and (b) identify compliance diagnoses for PTSD depending on the experience of aggression (presence of fear, helplessness, or horror during the aggression), the perceived severity of aggression, and socio-demographic variables (gender, age, profession, employment status, and work experience). The results show that the experience of aggression with fear, helplessness, or horror is associated with the presence of posttraumatic symptoms related to re-experiencing but is not related to avoidance and emotional numbing and arousal. Furthermore, the perception of aggression as severe was associated with the presence of symptoms related to re-experiencing. These results are presented and discussed.