Because of distributed nature, grid computing environments are easy targets for intruders looking for possible vulnerabilities to exploit [1]. By impersonating legitimate users, the intruders can use a service's abundant resources maliciously. To combat attackers, intrusion-detection systems (IDSs) can offer additional security measures for these environments by investigating configurations, logs, network traffic, and user actions to identify typical attack behavior. However, IDS must be distributed to work in a grid computing environment. It must monitor each node and, when an attack occurs, alert other nodes in the environment. This kind of communication requires compatibility between heterogeneous hosts, various communication mechanisms, and permission control over system maintenance and updates. We present the problem of grid intrusion; analyze the requirements of a system to detect them. In this paper we are discussing how IDS can be implemented for grid computing environment.