In this work a new approach based on multi-objective evolutionary algorithms (MOEA) is proposed for the routing and spectrum assignment (RSA) Problem in elastic optical networks (EON); where, given a set of unicast requests, the proposed MOEA minimizes (a) the total cost, and (b) the spectrum used, simultaneously under optical layer constraints. The test experimental indicates that the proposal is suitable for the RSA when it is compared to another MOEA of the-state-of-the-art considering different quality measures. Basically, the proposed MOEA sequences the requests to be served under random-and-cost based strategy while that considered the-state-of-the-art is just random.CONACYT – Consejo Nacional de Ciencia y TecnologíaPROCIENCIA