Abstract: Mobile adhoc network (MANET) is the network in which mobile devices are connected by wireless media and there is no centralized management and fixed network infrastructure. Generally, routing protocols in adhoc networks are classified into proactive, reactive and hybrid. One of the important challenges in hybrid routing properties is the security of these protocols. As ZRP hybrid routing protocol has not appropriate security features against black hole attacks, in this paper, we propose a security mechanism based on estimated latency of the route reply packets reaching the source node and selecting the shortest secure route and it is protected against black hole attacks and finally a new hybrid routing protocol is presented. After simulating this protocol by simulation toolNS2, The simulation result shows that the proposed protocol showed less failure compared to standard ZRP protocol in the presence of malicious nodes of black hole in terms of some parameters as quality of service (QOS) such as the packets loss, packet delivery ratio, end to end delay.