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The sleep is one of the important phenomen in biological rhythm. Sleep function are usually characterized as being physical and emotional protective and restorative. On the average people spend a third of their life in sleep, and people up to 30% of population suffer from sleep disorders. Sleep disorders are major psychiatric problems. This is a descriptive survey for studying sleep disorders (Insomnia, excessive somnolence, functional disorders) among nurses working at hospitals affiliated with Shahid Beheshti’s Medical Sciences University in this study 751 nurses aged between 20-45 years have participated by data collection using questionnaire and analysis by tests, the results indicated, the most of sleep disorders in insomnia (Initiating sleep 55.8%, maintaining sleep 72.4%, early awakefulness 52.7%, excessive somnolence 65.5% and parasomnia 26.9%). In additional, there has been significant correlation between the demographic factors such as age, sex, marriage, shiftwork, with sleep disorders. These results conclude that the presence of different kind of sleep disorders among the nurses is the indicator of relation between the nurse job with biological disorder of sleep ryteme.