BACKGROUND: Violence is frequent towards nurses in forensic mental health hospitals. Implications of this high risk environment have not been systematically explored. This paper explores occurrence of symptoms on post traumatic stress and their relationship to professional quality of life. METHODS: Self report questionnaires assessing symptoms of post traumatic stress and professional quality of life were distributed among psychiatric nurses in a high security forensic psychiatric unit with high frequency of violent behaviour. Relationships between post traumatic stress symptoms, forensic nursing experience, type of ward and compassion satisfaction, burnout and compassion fatigue were explored. RESULTS: The prevalence of post traumatic stress symptoms was low. Low scores were found on compassion satisfaction. Length of psychiatric nursing experience and low scores on compassion satisfaction were correlated to increased post traumatic stress symptoms. CONCLUSION: Although high violence frequency, low rate of post traumatic stress symptoms and low compassion satisfaction scores was found. High staff/patient ratio and emotional distance between staff and patients are discussed as protective factors.