Abstract: Objective: To explore the sleep disorder and its influencing factors in psychiatric nurses and internal medicine nurses. Methods: A sleep condition questionnaire was completed by 291 psychiatric nurses from two first-class tertiary psychiatric hospitals and 368 internal medicine nurses from one first-class tertiary general hospital. Results: Among the 659 nurses who were investigated, 460 nurses of them reported that they had experienced at least one kind of sleep disorder, accounting for 69.8%. The proportions of whom experienced sleep disorder among psychiatric nurses and internal medicine nurses were 68.7% and 70.7%, respectively. Gender, years in nursing service and reported history of alcohol use were identified to be significantly associated (P<0.05) with sleep disorder. Only 58 nurses (8.8%) who reported sleep disorder choose to see a doctor for their sleeping problems; while 86 nurses choose to take medication, accounting for 13.1%. Years in nursing service, reported history of smoking and alcohol use were identified to be significantly associated (P<0.05) with the choice of taking sleep-aid medications. Conclusion: The sleep disorder was a commonly observed problem among nurses. Nurses with male gender, more than 10 years of nursing services and history of alcohol use were more likely to suffer from sleep disorder. There were a very low proportion of nurses who actually sought for medical help for their sleep disorder. Specific prevention and treatment actions should be taken for nurses with different gender and years of nursing service, so as to improve the sleep disorder among nurses and improve the nursing service in the long run.