Denial of service (DoS) attack is a major class of security threats today. They consume resources of remote hosts or network and make them deny or degrade services for legitimate users. Compared with traditional Internet, the resources, such as bandwidth, memory, and battery power, of each node are more limited in mobile ad hoc networks (MANETs). Therefore, nodes in MANETs are more vulnerable to DoS attacks. Moreover, attackers in MANETs cannot only use IP spoofing to conceal their real identities but also move arbitrarily, which makes it a challenging task to trace a remote attacker in MANETs. In this paper, we proposed a zone sampling-based traceback (ZSBT) algorithm for tracing DoS attackers in MANETs. In our algorithm, when a node forwards a packet, the node writes its zone ID into the packet with a probability. After receiving these packets, the victim can reconstruct the path between the attacker and itself. Simulations were carried out to illustrate the validity of the algorithm; even with a little communication overhead.