The third pillar allows for and agrees upon the transfer of nuclear technology and materials to NPT signatory countries for the development of civilian nuclear energy programs in those countries, as long as they can demonstrate that their nuclear programs are not being used for the development of nuclear weapons.

Since very few of the nuclear weapons states and states using nuclear reactors for energy generation are willing to completely abandon possession of nuclear fuel, the third pillar of the NPT under Article IV provides other states with the possibility to do the same, but under conditions intended to make it difficult to develop nuclear weapons.

The treaty recognizes the inalienable right of sovereign states to use nuclear energy for peaceful purposes, but restricts this right for NPT parties to be exercised "in conformity with Articles I and II" (the basic nonproliferation obligations that constitute the "first pillar" of the Treaty). As the commercially popular light water reactor nuclear power station uses enriched uranium fuel, it follows that states must be able either to enrich uranium or purchase it on an international market. Mohamed ElBaradei, Director General of the International Atomic Energy Agency, has called the spread of enrichment and reprocessing capabilities the "Achilles' heel" of the nuclear nonproliferation regime. As of 2007 13 states have an enrichment capability.[11] Because the availability of fissile material has long been considered the principal obstacle to, and "pacing element" for, a country's nuclear weapons development effort, it was declared a major emphasis of U.S. policy in 2004 to prevent the further spread of uranium enrichment and plutonium reprocessing (a.k.a. "ENR") technology. [12] Countries possessing ENR capabilities, it is feared, have what is in effect the option of using this capability to produce fissile material for weapons use on demand, thus giving them what has been termed a "virtual" nuclear weapons program. The degree to which NPT members have a "right" to ENR technology notwithstanding its potentially grave proliferation implications, therefore, is at the cutting edge of policy and legal debates surrounding the meaning of Article IV and its relation to Articles I, II, and III of the Treaty.

Countries that have signed the treaty as Non-Nuclear Weapons States and maintained that status have an unbroken record of not building nuclear weapons. However, Iraq was cited by the IAEA and sanctioned by the UN Security Council for violating its NPT safeguards obligations; North Korea never came into compliance with its NPT safeguards agreement and was cited repeatedly for these violations,[13] and later withdrew from the NPT and tested a nuclear device; Iran was found in non-compliance with its NPT safeguards obligations in an unusual non-consensus decision because it "failed in a number of instances over an extended period of time" to report aspects of its enrichment program;[14][15] and Libya pursued a clandestine nuclear weapons program before abandoning it in December 2003. In 1991 Romania reported previously undeclared nuclear activities by the former regime and the IAEA reported this non-compliance to the Security Council for information only. In some regions, the fact that all neighbors are verifiably free of nuclear weapons reduces any pressure individual states might feel to build those weapons themselves, even if neighbors are known to have peaceful nuclear energy programs that might otherwise be suspicious. In this, the treaty works as designed.

Mohamed ElBaradei, Director General of the International Atomic Energy Agency (IAEA), has said that by some estimates thirty-five to forty states could have the knowledge to acquire nuclear weapons.[16