The present study was aimed to synthesize silver nanoparticles (AgNPs)using the extract of oyster mushroom Pleurotuscitrinopileatus and its use in antibacterial testing. This green synthesis approach of silver NPs is very fast, simple, environmentally friendly and economical. The initial confirmation of silver NPs synthesis was observed with the alteration of the colour of the solution from colourless to wine red. The prepared nano-material was further characterized by UV-Visible spectrophotometer, and transmission electron microscopy (TEM). The TEM revealed particle size of synthesized AgNPsbetween the range of 11-13 nm. The bactericidal efficacy of silver NPstested against Escherichia coli confirmed the lowest 50 µg/L concentration of silver NPs bactericidal. Therefore based the observations of the study silver NPsat the level of its 50 µg/L can be used for the purposes of potential water disinfection, killing of bacteria, disinfection of medical equipments, wound washings, preservation of food stuffs and in hand sanitization.