A Wireless Sensor Network (WSN) is a self-organized multi hop network that consists of a large number of sensor nodes. The efficiency of the sensor networks depends upon the routing protocol used. There are different routing protocols exists to extend the network lifetime by efficiently consuming the energy of the nodes. The nodes have limited energy resources and are battery powered. Therefore, designing an effective routing protocol that conserve scarce energy resources is the major critical issue in WSN. In this paper, a Fitness based Routing Protocol (FRP) is proposed to optimize energy efficient data transmission.