Mobile ad-hoc networks are improvised wireless network increasingly appearing in recent years as portable wireless devices. Due to remarkable characteristics such as lack of central coordination, infrastructure less, dynamic topology and nature of wireless communication, Mobile ad-hoc networks are vulnerable to many security threats. Many Intrusion Detection Systems (IDS) have been introduced to identify the possible attacks in the MANET. In this paper, we review different methods of detection systems and evaluate the systems that have been proposed prominently. © 2005-2013 JATIT & LLS. All rights reserved.