Combinatorial designs are powerful mathematical tools with comprehensive and simple algebraic structures. Recently, many researchers have used combinatorial designs as key predistribution schemes in wireless sensor networks (WSNs). Previous studies on security of WSNs are mainly concentrated on those networks containing nodes with the same capabilities. Further, investigations reveal that high reliability and lifetime on networks can be achieved through hierarchical heterogeneous wireless sensor networks, where a small number of sensor nodes have more energy, memory, and transmission capability. Inspired by scheme due to Lee and Stinson, we propose a key predistribution scheme for a clustered heterogeneous WSN using transversal designs. This proposed scheme assigns key chains to sensor nodes before deployment and separates key pool of each cluster by adding a pseudo-random generated number after deployment. The performance evaluation and security analysis show that our proposed scheme can provide better security with significant reductions on communication overhead and storage space than other key management schemes without compromising connectivity. Copyright © 2014 John Wiley & Sons, Ltd.