The Seventh Review Conference of the Biological Weapons Convention in December 2011 provides an opportunity to modernize the treaty to better address the challenges of the 21st century. The key to this modernization is to redesign the treaty's Confidence-Building Measures (CBMs), the only formal mechanism for increasing transparency and demonstrating compliance with the treaty, to address changes in the global scientific, health, and security environments since the end of the Cold War. The scope of the CBMs should be expanded beyond state-run biological warfare programs to encompass a broader array of threats to global security, such as biological terrorism, laboratory accidents, dual-use research, and disease pandemics. Modernizing the CBM mechanism to take into account these new risks would extend the transparency-enhancing benefits of CBMs to a range of new and important topics, such as biosafety, laboratory biosecurity, and dual-use research oversight; make the CBMs and the treaty itself more relevant to the concerns and priorities of more states; and build on progress made during the recent series of intersessional meetings. To accomplish this, the CBMs need to be revised to shift their focus from hardware, the dual-use capabilities relevant to the treaty, to software, the political and legal institutions that govern the development and use of these capabilities. A more modern CBM mechanism should encourage greater participation in the confidence-building process, improve international cooperation against the full spectrum of biological risks, and promote the goal of universal membership in the treaty.