The dissolution of the Soviet Union in December 1991 was a significant event in more ways than one. The Soviet Union, which had opposed the US for more than 40 years, disintegrated virtually overnight. The fears of a global nuclear holocaust hanging like a cloud throughout the Cold War were at last eliminated. However, this was not a moment of unalloyed optimism and there was the danger of an enormous power vacuum in a country that possessed almost 30,000 nuclear weapons spread across its vast territories. Such a political vacuum, coupled with the rising influence of organised criminal syndicates, triggered concerns that fissile materials or even complete nuclear weapons could be stolen and fall into terrorist hands. The reasons that organised criminal mafias were interested in the nuclear black market were the enormous gains for them in smuggling illegal products across international borders. During the 1990s, transnational criminal groups based in Russia and Italy had well-established infrastructure and trafficking channels to smuggle fissile materials or even suitcase-sized nuclear weapons from one country to another. After the disintegration of the Soviet Union, nuclear weapons and fissile material stockpiles were dispersed in many new countries that faced serious politico-military upheavals. Many people working in the nuclear industry also became involved in nuclear smuggling, making it very difficult to prevent insider theft. Fissile material, generally used for making a nuclear fission explosive device, includes Highly Enriched Uranium (HEU) and plutonium (plutonium-239). According to the latest estimates, a kilogramme of plutonium can sell for more than $ 500,000 on the nuclear black market. With such high market value, fissile material has been an unsurprisingly hot commodity in the international criminal underworld for the past two decades. In 2012, the US State Department expressed grave concerns that the attempted smuggling of critical nuclear materials in recent years enhanced the risk that terrorist groups could acquire the ingredients for a weapon of mass destruction. The first confirmed nuclear trafficking case in the former Soviet Union involved the diversion of approximately 15 kilogrammes of HEU allegedly stolen by an employee from the Podolsk nuclear facility in 1992. More than 10 additional high-profile cases of trafficking incidents involving HEU or plutonium occurred in the following two years. In August 1994, German police recovered 12 ounces of plutonium-239, later identified as having originated in Russia, from a Munich train station. The amount of plutonium-239 seized could have been used to poison all the water supply plants in Munich or to make a devastating ‘dirty bomb’ that would disperse radioactive particles in the air. In any case, the amount of plutonium recovered was enough to kill thousands of people but no concrete actions could be taken to stop the leakage of nuclear materials from Russia and cases of trafficking in nuclear and other radioactive material continued to make headlines in Russia, Lithuania, Ukraine and other former Soviet republics. Some experts are of the view that most nuclear trafficking cases involve low-grade materials passed off by scam artists as the real thing and journalists generally misconstrue and exaggerate the threat. Admittedly, some analyses might be exaggerated but there is enough evidence available to give credence to a nightmare scenario involving 100 kilogrammes of fissile material stolen from Russia for sale on the nuclear black market. George Tenet, a former CIA director, explained in detail in his book, At the Centre of the Storm, that by 2002 the CIA had reliable information of senior al Qaeda leaders in Saudi Arabia negotiating for the purchase of three Russian tactical nuclear devices but it remains unclear if those negotiations were successful or not. The collective failure to strengthen export control laws and extremely porous borders of the former Soviet republics further complicate the efforts to combat nuclear proliferation and illicit sale on the black market. According to confirmed intelligence reports, some of the nuclear materials left Russia on their way to buyers via Georgia, which has emerged as a key transit point for various illegal materials due to its geography, unsecured borders, internal conflict and corruption. Organised and professional criminal groups are also involved in this type of trafficking. In 2006, a group of smugglers from Georgia were arrested attempting to sell HEU. In addition, there is the serious threat that various amounts of uranium and plutonium seized in different countries might be the tip of the proverbial iceberg. No one knows the exact amount of fissile materials that terrorists or criminal syndicates might have succeeded in smuggling to their desired destinations. For instance, in 1994, the Czech police found, during the investigation of a case involving 2.7 kilogrammes of HEU stolen from Russia, that smugglers had promised to deliver to buyers an additional 60 kilogrammes of HEU over the next 12 months. After many years of searching, authorities have remained unable to trace the location of many kilogrammes of critical material in the possession of smugglers. Nuclear smuggling and illicit proliferation of nuclear weapons pose a dangerous and persistent threat to international security. The 9/11 attacks in the US and successful terrorist incidents in a number of European countries have already demonstrated that al Qaeda is prepared to use indiscriminate means and the most violent force to pursue its aim of global domination. In order to thwart unauthorised use of fissile or radiological materials, it is important to recognise that nuclear trafficking is a global challenge involving a broad spectrum of threats. The responsibility to counter this threat can no longer be left in the hands of individual nations. A retrospective analysis of theft and smuggling cases, and the vast potential of the nuclear black market enable us to understand the extent of proliferation-related damage that has occurred so far and the challenges we could face as a result of it in the years to come. The writer is a research scholar and a former visiting fellow at the Monterey Institute of International Studies, California. He can be reached at rizwanasghar7@hotmail.com