Mohammad Marhamati - Master of science, department of Industrial management, faculty of management and economic, Tarbiat Modares University, Tehran, Iran
Adel Azar - Professor of management, department of Industrial management, faculty of management and economic, Tarbiat Modares University, Tehran, Iran
Maryam Kolyaei - Master of science, department of Industrial management, faculty of management and economic, Tarbiat Modares University, Tehran, Iran

Green supplier selection has become necessary as organizations increasingly force with increasing government regulation and stronger public awareness. The purpose of this study is to present a multi -objective Non-linear programming (MONLP) for two of the most critical tasks in supply chain management, supplier selection and order allocation. In this study Fuzzy AHP is applied first for analyzing the weights of the multiple objectives. The objective functions minimize total cost, total time, total of defective product, and Green House Gas Emission and one of them maximizes total quality level. The utilization of the proposed model is investigated with a case study in Iran. We adopted Genetic Algorithms to find the Local-optimal solution. The results used to identifying green suppliers in the company as well as to achieve optimal allocation of orders among the suppliers. Also we compared the optimal results of objective functions, before and after considering the carbon emission problem, to help the manufacture to take the best decision by a trade-off between environmental consideration and cost, time, quality and defective product objectives.

Green supplier selection, Fuzzy AHP, Optimization mathematical programming, Genetic algorithm