Previous research conducted on the study of regimes has focused little attention on the area of security regimes, and more specifically, on the nuclear, chemical, and biological (NBC) nonproliferation regimes. Prior inquiries into this area have argued that security regimes are difficult to establish; however since the establishment of the NBC regimes, they have had a significant impact on these issue areas. This study takes regime theory further by investigating the effectiveness of the NBC regimes using a structured, focused comparison of the three cases. This in-depth comparison further reinforced that the nonproliferation regimes have had a positive impact in slowing the pace of proliferation in these areas. In addition, the chemical weapons regime demonstrated that its challenges verifying the transfer of scheduled chemicals and their related materials, and the even enforcement of policy call into question the regimes long-term ability to successfully carry out its mandate. The assessment of the nuclear nonproliferation regime demonstrated that over time states can lose faith in a regime if some portions of its mandate are carried out more fully than others. Finally, analysis of the biological weapons regime revealed that a lack of confidence in state adherence to the regime coupled with the absence of structure which can validate information leads to an organization which is unable to provide its members with the promise of security. Overall, these findings challenge the theoretical application of regimes within an important area of international policymaking.