Although engineered silver (Ag) nanopowders offer great promise in various fields of biomedical, industrial and ecological applications, insufficient data is known about their cytotoxicity. The purpose of the present study was the synthesis and then the determination of cytotoxicity effect of Ag powders using the pyrosol method, at various temperatures of 600°C, 650°C and 700°C, respectively by sol-gel method and heat treatments at 500°C, 600°C, 700°C and 800°C. From the structural, compositional and morphological point of view, Ag samples were characterized by using X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) coupled with selected area electron diffraction (SAED) techniques. There is an influence of the synthesis route on Ag particles, which is shown as their cytotoxicity, different sizes of micro and nanosilver synthesized powders, which were evaluated in comparison depending on the work methods. Their cytotoxicity was evaluated based on their influence on cellular morphology and proliferation rate, cell cycle and apoptosis of undifferential stem cells, endothelial cells and tumoral cells, assessed through flow cytometry, cloning and MTT assay. The results showed that the cytotoxicity of the obtained Ag nanoparticles (NPs) depends on the synthesis route, the pyrosol synthesized NPs exhibiting a higher cytotoxicity as compared to those obtained by the sol-gel method.