Nanosciences and nanotechnology can be considered as resources for the humankind, providing innovative tools and devices for the protection and decontamination from chemical, biological, radiological or nuclear (CBRN) warfare agents. At the same time, these disciplines may offer unprecedented and uncontrolled means of mass destruction, by the synthesis of novel and more effective aggressive agents or by improving the production capability of intentionally toxic systems. A multidisciplinary approach, with experts active in various fields, such as chemistry, physics, biology and materials science, is needed to have a strict control on potential illegal uses of nanosciences and nanosystems.