fa Mathematical Modeling and Applications of OR Mathematical Modeling and Applications of OR پژوهشی Original  In this paper, we consider a multi-objective hub location problem (MOHLP) to locate two constrained    facilities in order to minimize the distance between these facilities and the weighted distance between each facility and related customers. For this purpose, we establish a necessary and sufficient condition of optimality for finding an efficient solution of the problem. We show that MOHLP can be reduced to a simple bi-level distance problem. Then we develop an efficient algorithm to find the optimal solution set of BDP,  and provide its convergence without any assumption. Moreover, an algorithm is proposed to solve MOHLP, which converges in a finite number of iterations. Some examples are stated to clarify the proposed algorithms. 34 48 http://iors.ir/journal/browse.php?a_code=A-10-1422-38&slc_lang=fa&sid=1 Ali Ansari Ardali Ali Ansari Ardali ali.ansariardali@sci.sku.ac.ir 1111111111 1111111111 Yes Shahrekord University Shahrekord University Ahmad Reza Raeisi Dehkordi Ahmad Reza Raeisi Dehkordi a.raisi@sci.ui.ac.ir 1111111111 1111111111 No Isfahan University Isfahan University