Background and Purpose: Holy Quran has mentioned sleep in several verses and has attributed the possibility of human sleep at night and during the day to divine signs and has known it as the reason of feeling comfortable. In the study of Islamic narrative resources the word “sleep” has been observed 6031 times and some words such as “to sleep”, which is among its synonyms, have been observed 2639 times. According to av Sina the first priority in “six essential principles” is exercise(sport) , the next priorities are eating and drinking, and sleeping is afterwards . To evaluate the importance of sleep, it’s sufficient to mention that deprivation of sleep in several days in a row will lead to death. So both traditional and modern medicine have paid particular attention to it.
The adequate and required sleep for adults during the day is 6 to 8 hours, although sleep timing and its structure vary according to the age and so forth. Currently 30 to 45 percent of people suffer from one of the sleep disorders. Insomnia is the most prevalent sleep disorder which might be temporary, short-term, long-term, and chronic and the root causes need to be assessed closely. Chronic, recurrent insomnia forms a fairly rampant group of sleep disorders. In the incipient insomnia, at least for one month, the main complaint is the difficulty at the beginning and the continuity of  sleeping as well as the deficiency of comfort and alacrity after sleep.
Methods and Materials: The methodology of this study has been gathered comprehensively from libraries and has used traditional and modern medicine resources and scientific articles. Subjects related to the reasons of insomnia and symptoms and complications stemming from insomnia have been introduced in both isms and with comparative study of these two, it has been ultimately concluded that the discussed reasons and complications for insomnia. 
Conclusion: The widespread medicine, traditional medicine and Islamic resources have offered comprehensive issues related to sleep, sleep disorders, reasons and its solutions. Insufficient sleep and insomnia have been argued with the devised term “ sahr ” in traditional medicine resources and the term “insomnia” in modern medicine resources. The reasons for insomnia in traditional medicine are pain, sorrow, happiness, fury and so forth and in modern medicine insomnia stems from internal diseases or mental diseases along with innumerable complications.