Purpose: The purpose of study was to identify violence episodes by patients and/or their guardians and responses from emergency room nurses. Method: A convenient sample of 172 emergency nurses was selected from general hospitals with more than 200 beds. A survey design was used and data were collected from October 2 to October 11, 2006. using self-report questionnaires which were developed by the authors. Descriptive statistics, with the SPSS PC program were used to analyze the data. Results: The majority of nurses(97.1%) had experienced violence by patients or their guardians in the previous month. Violence offenders who were drunk comprised 68.6% of total offenders. Causes of violence were delays in examination and treatment(59.9%). The major coping behavior in dealing with violence episodes was ignoring(40.1%). Responses to violence experienced by emergency nurses were rated as 2.39. Response to violence according to general characteristics of the nurses showed no statistically significant differences. Conclusion: Considering the high prevalence of violence experienced by emergency nurses, hospitals must develop and manage preventive education programs and policy.