The article deals with achievements of present-day genetics and with threats to security they potentially can bring. The substance of the problem is in the fact that discoveries of biology at the threshold of the third millenium not only promote development of bio-technology and progress in medicine, agriculture and different branches of economy, but create scientific-technological elements for working out advanced biological means of mass destruction, what makes them very attractive for terrorists. Achievements in molecular biology, micro-biology and genetic engineering can also be used for anti-humanistic aims, applying synthesized substance as the newest types of biological weapons. Biology always was considered as a «science of life». In our days it can become, quite unexpectedly, a science bringing death. Dynamic growth of terrorism has brought us to the change of priorities in evaluation of possible threats to national security in many countries of the world. Now the overwhelming majority of experts in the list of the less controlled and the most dangerous threats to the mankind name bio-aggression, bio-terrorism and «ecological wars».