Because all vulnerabilities of a network cannot be realized and penetration of the system cannot always be prevented, Intrusion Detection Systems (IDS s) have become necessary to ensure the security of a network. A great deal of research has been conducted on intrusion detection in a wired environment; however, new issues arise when trying to implement an IDS in a mobile, ad hoc environment. This paper discusses considerations when designing an IDS for a mobile, ad hoc network and describes an architectural model for IDS s that takes into account these and other pre-existing considerations.