The transnational exchange of forensic DNA data has become a modern trend in fighting cross-border crime, terrorism and illegal immigration. Forensic DNA data allow the police to identify, eliminate or link individuals associated with a crime. Additionally, different crime scenes can be linked via the DNA profile to identify serial offenders or determine crime patterns. Approaches to the transnational exchange of DNA data can be categorized into four: (1) creation of an international DNA database, (2) linked or networked national DNA databases, (3) request-based exchange of data, and (4) a combination of these. Most countries operate the combination system of data exchange. This paper briefly introduces the different approaches in the transnational sharing of forensic DNA data, the legislative and operational framework, pattern of data exchange and participating states, and policy challenges associated with data sharing. Generally, most DNA exchange systems are modelled as the European Union Prüm regime. This operates under two stages: hit/no-hit query and further information sharing. The scope of the data exchange is governed by individual national legislation that determines the type of information that can be shared and the national authority responsible for the system. Though DNA data exchange has been instrumental in resolving serious crimes such as gang and serial rape, and armed robbery, adequate information about their overall effectiveness and efficiency is lacking. Further, operational, legal and ethical challenges including issues of privacy and proportionality appear to limit the full potential of the DNA data exchange system.