The aim of the study is to determine the frequency rate of the principals of the public schools and institutions of Ministry of National Education in the years between 2001 and 2011. By the study, the average duty periods of the principals of the public schools and institutions are investigated according to the type of educational institutions and additonally the effect of social-economic environment of the schools on the frequency rate of the principals of the public schools and institutions are investigated. The study was performed as a descriptive study. The sampling of the study is the all public formal and non-formal educational institutions of Ministry of National Education in İstanbul. According to the results of the study, between 2011 and the year 2010 when the rotation application started in, the average duty period of the principals of the public schools and institutions in İstanbul between the years 2001-2010 is 4,91 years. The results of the study parallel to the findings of the literature. According to the findings of the study, the principals of the schools which have the most advantageous socio-economic environment have the tendency to work longer in their schools. This study which will provide the data with the “rotation” discussions among the educators will make an important contribution to Turkish educational literature.