against countries that have been implicated in the development of weapons of mass destruction and the use of terrorism. These sanctions have included limitations on customary trade and/or financial relations with a target country. Are sanctions effective in discouraging the proliferation of weapons of mass destruction? This paper investigates the nature and effects of sanctions applied to North Korea, Iran and Iraq. The paper concludes that although sanctions may help slow down the development of weapons of mass destruction, it is unlikely that they will be able to prevent determined and well financed countries from becoming members of the nuclear club. In the absence of military conflict, policymakers should reinforce the effectiveness of sanctions by being ready to negotiate and offer positive incentives as a method of encouraging cooperation with target nations.