The objective of the study was to evaluate the reducing properties of the aqueous extract of cranberry (Vaccinium corymbosum) at concentrations of 1 mM and 10 mM in the process of green synthesis of silver nanoparticles (NP Ag), starting from the precursor silver nitrate (AgNO3). The samples were initially evaluated by UV-Vis spectrophotometry, which determined in the foreground the presence of nanostructures, since the surface plasmon resonance peaks were in the range of 408 and 412 nm respectively, in turn the dispersion results of dynamic light (DLS) reported information related to the hydrodynamic size and polydispersity of the colloidal solution, as far as the size was concerned, measurements of 9.74 and 13.67 nm were obtained, and with a tendency to be monodisperse; TEM images corroborate the aforementioned results. The results suggest the potential reducing effect of bilberry extract, in turn a higher molar concentration generates a better formation of the nanostructure and higher production of this.