Terrorists can be a little more ambitious in selecting their instruments of harm, at times even venturing to employ decidedly unconventional means – the most infamous of which include chemical, biological, radiological and nuclear (CBRN) weapons. The specter of such weapons being used against unprotected victims – especially in the form of so-called weapons of mass destruction (WMD) – has become a source of substantial concern for both governments and publics around the world, often conjuring up terrifying images of pestilence and mushroom clouds. The chapter attempts to untangle the opposing views about CBRN terrorism, by exploring why terrorists might be attracted to CBRN weapons over guns and bombs and what types of capabilities are required to successfully utilize them. In so doing, it briefly considers the nature and magnitude of the CBRN terrorism threat both at present and in the future. The category of terrorist motivations for pursuing CBRN weapons are organizational motives.