en تحقیق در عملیات Operations Research پژوهشي Research This paper deals with multi- objective nonlinear programming problem having rough intervals in the constraints. The problem is approached by taking maximum value range and minimum value range inequalities as constraints conditions, reduces it into two classical multi-objective nonlinear programming problems, called lower and upper approximation problems.  All of the lower and upper approximation problems may be solved using the weighting method, where an optimal rough interval solution is obtained. The stability set of the first kind corresponding to the optimal rough interval solution is determined. An illustrative numerical example is given to clarify the obtained results. Multi- objective nonlinear programming, Rough intervals, Rough efficient solution, weighting problem, Optimal rough interval solution, Parametric studyک 407 413 http://ijiepr.iust.ac.ir/browse.php?a_code=A-10-1183-1&slc_lang=en&sid=1 Hamiden Abdelwahed Khalifa hamiden_2008@yahoo.com 180031947532846005574 180031947532846005574 Yes ISSR- Cairo Unoversity