The mission of the Office of Nonproliferation and International Security (NIS) is to prevent the proliferation of nuclear weapons, materials, technology, and expertise. NIS applies technical and policy expertise to execute programs that:
- The Office of Nuclear Safeguards and Security 
Safeguard and secure nuclear material and facilities to prevent diversion, theft, and sabotage.
- The Office of Nuclear Controls 
Facilitate legitimate nuclear cooperation by strengthening domestic and global capacity to control the illicit transfer of WMD dual-use material, equipment, technology, and expertise.
- The Office of Nuclear Verification 
Develop policy and technical solutions for transparent nuclear reductions and treaty monitoring and compliance.
- The Office of Nonproliferation and International Security Policy 
Develop crosscutting policy and technical solutions and programs and strategies to reduce nuclear dangers.