MANET is the compilation of wireless portable nodes which dynamically arranges a short term network without the use of any centralized administration or network infrastructure. Routing protocols used in mobile ad hoc networks must mechanically change to environments that can vary between the extremes of low mobility with high bandwidth, and high mobility with low bandwidth. Various secure routing protocols are proposed for mobile ad hoc networks. In this paper, a performance analysis of three MANET routing protocols-AODV, DSR and Sec-AODV are performed.