In Mobile Ad-hoc NETworks (MANETs) nodes communicate directly with each other when they are both within the same communication range. Otherwise, they rely on their neighbors to relay messages. The open medium and wide distribution of nodes or the lack of centralized infrastructure make MANET vulnerable to malicious attackers. Security has become a primary concern in order to provide protected communication between mobile nodes in a hostile environment. Hence providing secure route is the most challenging task to be carried out in MANET environment. This paper proposes a unified trust management scheme for MANETs to provide secure routing. In this scheme every node calculates the trust value of its one hop neighbor by both direct observation and recommendations provided by other neighbors.