While there is no doubt that some information on nuclear weapons must remain undisclosed, excessive nuclear secrecy hinders progress toward the twin goals of improved nuclear materials security and the eventual elimination of nuclear weapons worldwide. With the March 2012 Nuclear Security Summit afoot and the 2015 Nuclear Non-Proliferation Treaty Review Conference in sight, now is the time for nuclear weapons states to implement new transparency measures such as declaring additional information regarding the capabilities, size, and purpose of weapons stockpiles and fissile materials, and providing the means to verify a larger portion of those declarations. Increased transparency can reduce uncertainty, build trust, establish baselines for future reductions, and place political pressure on other states possessing nuclear weapons to take similar steps. Because they possess the vast majority of nuclear weapons and fissile material in the world, the United States and Russia should lead the way by creating a model for declarations, including non-deployed and nonstrategic weapons. Declarations of nuclear weapons and fissile materials could be verified bilaterally, through new multilateral agreements and a multilateral inspections agency or by expanding the role of the International Atomic Energy Agency. Some transparency actions can be taken immediately, either unilaterally or reciprocally. Increased transparency can provide short-term benefits for some states and establish a foundation for additional bilateral and multilateral nuclear arms reductions. Transparency can be embraced by non-nuclear weapons states and states with nuclear weapons outside of the Nuclear Non-Proliferation Treaty without undertaking new treaty obligations.