The aim of this study is to assay effects Nuclear Power Plant (NPP) accidents on biodiversity and to point out the Metsamor Nuclear Power Plant (MNPP) accident risk in Eastern Armenia. Contemporary literature evaluated for this purpose. NPP accidents effect on the animals and plants in several ways such as increased morphologic, physiologic, genetic disorders; increased mutation rates and developmental abnormalities, increase in general oncological morbidity, accelerated aging, reduction in body antioxidant levels (physiological and genetic effects of radiation) and reduced adult survival and reproduction suggests; reduction in species abundance (ecological consequences of radiation). Several studies that were conducted on MNPP indicated the combination of design (old technology and unsatisfactory safety measures) and location (exposed to severe seismic waves) of MNPP demonstrated a high possibility of accidents. Previous studies indicated that NPP accidents cause permanent damage to biodiversity. Recent publications indicate that if an accident happens at MNPP, Turkey, Azerbaijan, Georgia, and Iran might be influenced. Because of this reason it need to have an urgent action plan and take the necessary precautions for this possible catastrophe.