This is a descriptive research, which aimed to determine the factors leading to turnover of Iranian nurses employed in Tehran, Iran and Shaheed Beheshtee Universities in a decade between 1989-1999.The data were gathered by a valid structured questionnaire. With referring to the research settings, the researcher got the address of nurses who had left their jobs form 1989 to 1999.The researchers, then, sent them the predetermined questionnaire as well as a cover letter and an stampeded envelope and asked them to fill the options and return them by regular mail. At whole 52 questionnaires were sent back and 51 were considered as correct and analyzed. 35.3% of subjects were among the age group of 25-29. 66.5% were female, 91.2% were married, 82.3% were university graduates and 91.5% were working as clinical nurses in hospitals.Working in changing shifts (49.2 %) and high load working (53.4%) were mentioned as two important factors for their job leaving. L Considering the work conditions as unpleasant, most of them (72.3%) didn't like to return to their works. The turnover emerged reasons in this study were classified as follows: 1- Being deprived of accommodations facilities. 41.2%2- Low salaries. 64.7%3-Poor Social position of nurses and ranking nursing among non-scientific jobs.54.9%4- Being ignored by managers and supervisors, and getting no support on the part of them, when necessary 70.6%.