The aim of this study was to synthesize silver nanoparticles (AgNPs) at different concentrations and evaluate their physicochemical, antimicrobial properties and determine the cytotoxicity of these nanoparticles. The AgNPs were synthesized by the alcohol reduction process, which consists of the reduction of AgNO3 and its subsequent stabilization by PVP at 80°C for 4 h. In this study, the molar ratio between AgNO3 and PVP and the average molecular weight were modified. The UV-Vis spectrum showed characteristic surface plasmon resonance absorption peaks at about 415 nm for all samples. X-ray diffractograms showed diffraction peaks related to the face-centered cubic structure of metallic Ag. These nanoparticles were uniform in size and shape and their dimensions can be controlled in the range from 3 to 800 nm. For antimicrobial activity, MIC solutions showed greater susceptibility of planktonic cells of Candida albicans. The determination of the inhibition halo showed that the silver nanoparticles have an effect on the microorganisms Streptococcus mutans, Candida albicans and Actinomyces israelii. Lower concentration composition produce a lower cytotoxic effect than particles with high concentration. It is concluded that molar ratio between AgNO3 and PVP in the production of AgNPs was essential.