Au-Ag bimetallic nanoparticles have been fabricated by one-step simple electrochemical deposition method using ionic liquid as green electrolyte (1-butyl-3-methylimidazolium tetrafluoro borate). Fabricated Au-Ag bimetallic nanoparticles have been characterized using cyclic voltammetry (CV), FE-SEM, UV-vis spectroscopy, and X-ray diffraction (XRD) studies. The electrodeposited Au-Ag bimetallic nanoparticles were found in the size range of 16-30 nm, respectively. This type of Au-Ag bimetallic nanoparticles could be directly applied for the optoelectronic and biosensing applications.