en تخصصي Special پژوهشي Research Modeling and solving real world problems is one of the most important issues in optimization problems<span dir="RTL">.</span> In this paper, we present an approach to solve Fuzzy Interval Flexible Linear Programming (FIFLP) problems that simultaneously have the interval ambiguity in the matrix of coefficients<span dir="RTL"> .</span>In the first step, using the interval problem solving techniques; we transform the fuzzy interval flexible problem into two optimistic and pessimistic sub-problems. Then, in the second step, using a multi-parametric approach, we solve two fuzzy flexible sub- problems and finally the results are investigated with numerical example<span dir="RTL">.</span><br> &nbsp; Interval Linear Programming, Fuzzy Interval Flexible Linear Programming, –efficiency, –feasibility, Multi-parametric Approach 19 29 http://ijorlu.lahijan.iau.ir/browse.php?a_code=A-10-467-1&slc_lang=en&sid=1 F. Mahmoudi فرانک محمودی 10031947532846001047 10031947532846001047 Yes Department of mathematics, University of Mazandaran, Babolsar, Iran