or in the telecommunications field. While VoIP offers a similar general service to traditional telecommunication services and is based on similar infrastruc- tures (such as e-commerce), VoIP services are, however, based on a different set of signaling protocols, access technologies and business plans. Hence, extrap- olating state-of-the-art fraud detection schemes to VoIP is unfortunately not straightforward and requires at least the extension of these approaches to take the specific nature of VoIP into account. Further, the techniques developed to face the fraud problems in telecom- munication networks and credit card services are usually designed with the assumption of large and centralized databases and the availability of suffi- ciently large hardware and software resources. This has lead to the design of often inefficient, unflexible and very complex schemes that are not adequate for the distributed and open nature of VoIP services. In this chapter, we suggest a conceptual fraud detection framework for detecting fraud and misuse in VoIP environments. Here, for clarity purposes, the framework under consideration will be called SAFER. In the latter, the above-mentioned anti-fraud techniques will be improved in terms of perfor- mance and applicability to the VoIP environment. Moreover, the following new themes will be addressed. 1. New vulnerabilities consideration: The emerging VoIP technologies also brought new threats and vulnerabilities. These threats are especially crucial in cases where operators are interfacing with each other and to the users through servers connected to the public Internet. A great amount of work can be found in the literature about monitoring and fraud detection. However, this work mainly targets financial transac- tions through web applications or misuse of services provided by mobile operators and does not take into account the very specific characteristics of the VoIP protocols such as SIP, DNS/ENUM, RTP/RTCP and many others. As a consequence, the SAFER framework will not only inve