Security in Wireless Sensor Network (WSN) has become a key issue due to demanding areas in which WSNs are being applied. With scarce resources in sensor nodes seasoned techniques like Diffie-Hellman, RSA and elliptic curve cryptography (ECC) cannot be used because they have resource demanding computations. Key pre-distribution has proved to be the most feasible amongst key management schemes in WSNs. Research work in key management continues to take center stage due to its importance amongst security primitives in WSNs. An improved energy efficient key management scheme (IEEKDM) for large scale WSNs is proposed in this paper. Simulations conducted show that our scheme performs very well and conserves energy.