Background. Many nations are able to prosecute transplant-related crimes committed in their territory, but transplant recipients, organ sellers and brokers, and transplant professionals may escape prosecution by engaging in these practices in foreign locations where they judge the risk of criminal investigation and prosecution to be remote. Methods. The Declaration of Istanbul Custodian Group convened an international working group to evaluate the possible role of extraterritorial jurisdiction in strengthening the enforcement of existing laws governing transplant-related crimes across national boundaries. Potential practical and ethical concerns about the use of extraterritorial jurisdiction were examined, and possible responses were explored. Results. Extraterritorial jurisdiction is a legitimate tool to combat transplant-related crimes. Further, development of a global registry of transnational transplant activities in conjunction with a standardized international referral system for legitimate travel for transplantation is proposed as a mechanism to support enforcement of national and international legal tools. Conclusions. States are encouraged to include provisions on extraterritorial jurisdiction in their laws on transplant-related crimes and to collaborate with professionals and international authorities in the development of a global registry of transnational transplant activities. These actions would assist in the identification and evaluation of illicit activities and provide information that would help in developing strategies to deter and prevent them.