This study sought to determine the frequency and types of violence that occurred during the previous year against health care workers in emergency departments in Denizli, Turkey, and to discern the views of workers on the prevention of such aggressive behavior. This study was conducted from March 1 to April 15, 2003, and included a group of 79 health care workers from the emergency departments of 3 hospitals in Denizli, namely, the Hospital of Pamukkale University Medical Faculty, the City Hospital of Denizli, and the Hospital of the Social Insurance Foundation. Data were collected from a self-administered questionnaire. In all, 88.6% of participants had been subjected to or had witnessed verbal violence, and 49.4% of them had been subjected to or had witnessed physical violence during the previous year. The most frequent reason (31.4%) for violence was abuse of alcohol and drugs by perpetrators. The second most frequent reason (24.7%) was the long waiting times typical of emergency departments. The most common type of violence was loud shouting; swearing, threatening, and hitting were the next most frequent violent behaviors. In all, 36.1% of subjects who had experienced violence reported that they developed psychological problems after the incident. Most participants commented on the insufficiency of currently available security systems within emergency departments and on the need for further training about violence. All health care personnel within emergency departments should be aware of the risk of violence and should be prepared for unpredictable conditions and events; in addition, security systems should be updated so that violence within emergency departments can be prevented.