fa عمومى General پژوهشي Research The purpose of this study is to utilize a new method for ranking extreme efficient decision making units (DMUs) based upon the omission of these efficient DMUs from reference set of inefficient and non-extreme efficient DMUs in data envelopment analysis (DEA) models with constant and variable returns to scale. In this method, an L2- norm is used and it is believed that it doesn't have any existing problems of such methods. Finally, two numerical examples for illustration and comparing the proposed method with other ranking approaches are presented. Keywords: Data Envelopment Analysis (DEA), Ranking, Efficiency. 65 73 http://ijorlu.lahijan.iau.ir/browse.php?a_code=A-10-2-11&slc_lang=fa&sid=1 R. Eslami Roba_eslami@azad.ac.ir 100319475328460064 100319475328460064 Yes Department of Mathematics, South Tehran Branch, Islamic Azad University, Tehran, Iran. M. Khoveyni 100319475328460065 100319475328460065 No Department of Mathematics, Shahr-e-Ray Branch, Islamic Azad University, Tehran, Iran.