[Excerpt from authors] Introduction: Burnout is a phenomenon in which the cumulative effects of a stressful work environment gradually overwhelm the defenses of staff members, forcing them to withdraw psychologically. This study compared the levels of burnout among nurses in different nursing specialties. Materials and methods: The sample of the study consisted of all the nurses working in all public hospitals in Shiraz, Iran who were graduates of either technological educational institutions or universities and had experienced clinical nursing practice for at least 1 year. Using Maslach Burnout Inventory and General Health Questionnaire (28-item version), we identified the psychiatric morbidity and burnout among nurses. Results: Study results indicated that nurses of psychiatry wards showed significantly higher levels of emotional exhaustion and depersonalization in comparison with nurses working in other wards, and burn wards nurses showed significantly higher levels of personal accomplishment. Also, nurses who were single were more emotionally exhausted. Conclusion: Different clinical working environments appear to have an impact on the development of nurses' burnout.