ZigBee is a wireless sensor network protocol recognized as a next-generation standard infrastructure for WBAN and Smart Grid. Security plays an important role in several ZigBee applications. Especially, strict membership control should be enforced when the membership is changed during the join and leave operations in ZigBee. In this paper, we investigate the security weakness of the current leave operation in ZigBee and propose a new security scheme to address it as well as its security and performance analysis.