International Regulatory Co operation : Addressing Global Challenges The world is becoming increasingly global. This raises important challenges for regulatory processes which still largely emanate from domestic jurisdictions. In order to eliminate unnecessary regulatory divergences and to address global challenges pertaining to systemic risks the environment and human health and safety governments increasingly seek to better articulate regulations across borders and to ensure greater enforcement of rules and their application across jurisdictions. This report gathers in a synthetic manner the knowledge and evidence available to date on the various mechanisms available to governments to promote regulatory co operation and their benefits and challenges. The review of evidence confirms the increased internationalisation of regulation which takes place through a wide variety of mechanisms and multiple actors and highlights a shift in the nature of IRC from complete harmonisation of regulation to more flexible options such as mutual recognition agreements. Despite growing regulatory co operation however decision making on IRC is not informed by a clear understanding of benefits costs and success factors of the diverse IRC options.