Non-proliferation, in its strictly meaning, is a system for the control andprevention of making new nuclear states. While the Nuclear Non-Proliferation Treaty (NPT) has been enforced for more than three decades and the UN Security Council as well as the IAEA Board of Governors have issued many resolutions on this matter, they could not transform it into UN international customary norm. This Article analyzes the non-proliferation regime and its international legal nature as a conventional or customary norm. The author believes that the discriminatory rights and duties of the NPT's state parties that is unconformity with the equal sovereignty of states, have impeded the opinio juris necessary to formation of a custom as an important part of international community. In addition, enforcing a system by some states under an inevitable condition and within a political impulsion environment can not necessarily emerge the opinio juris or collective opinion in the international community.
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