This chapter examines the troubled relationship between the various legal regimes under which states cooperate to suppress crime and the protection of human rights, specifically the procedural human rights of individuals targeted for investigation in transnational cases. It provides an analysis of what rights protections exist in the context of the suppression treaties themselves, and also whether and to what extent international human rights law imposes obligations on states when they engage in inter-state cooperation in criminal matters (eg extradition, mutual legal assistance). It concludes that despite the topic being an active one for some decades, relatively few hard human rights norms can be found in this setting, and ponders the limitations of political will and implications for the rule of law.