The green synthesis of nanoparticles is one step toward the sustainable development. Green tea extract was used as a source for synthesizing bimetallic Au-Ag Nanoparticles. These bimetallic nanoparticles were characterized by UV spectroscopy and TEM examination, which revealed the particles have core and shell structures. Bimetallic NPs have shown promising antibacterial, antifungal and antioxidant activity.