In this study, a rapid, simple approach was applied for the synthesis of silver nanoparticles using Pistia stratiotes aqueous leaf extract. The plant extract acts both as a reducing agent and as a capping agent. To identify the compounds responsible for the reduction of silver salt, the functional groups present in plant extract were investigated by FTIR (Fourier-Transform Infrared Spectroscopy). Various techniques used to characterize synthesized nanoparticles are surface morphology and particle size analysis by TEM (Transmission Electron Microscopy) and UV- visible spectrophotometer showed an absorbance peak in the range of 422 nm, surface morphology analyzed by SEM (Scanning Electron Microscopy), elemental analyzed by EDX
(Energy-dispersive X-ray spectroscopy), and Crystallinity analyzed by XRD (X-ray Powder Diffraction). The silver nanoparticles showed antibacterial activities against gram-negative (Escherichia coli) microorganisms. Results confirmed this protocol as simple, rapid, one-step, eco-friendly, non-toxic, and an alternative to conventional physical/chemical methods. Only 30 min were required for the conversion of silver salt into silver nanoparticles at room temperature, without the involvement of any hazardous chemical.