One of the most essential needs in nanotechnology is to develop eco-friendly and green approaches in nanoparticle synthesis. This study reports on the synthesis of silver nanoparticles (AgNPs) using the aqueous extract of Sesbania grandiflora leaves. The formation of AgNPs was confirmed by the visualization of signatory yellow color formation from colorless solution and UV-Vis spectra. X-ray diffraction analysis reveals the face centered cubic structure of AgNPs with good crystalline nature. Well-dispersed and spherical shaped AgNPs with nanorange size was evidenced by the morphological studies. Energy dispersive X-ray spectroscopy analysis attested the presence of metallic silver at ~3 keV. UV-Vis absorption spectra depicts only single maximum absorption band which confirms the formation of spherical nanoparticles. FTIR spectrum indicates the involvement of different functional groups in both reduction and capping mechanisms of nanoparticles formation. The antimicrobial activity of AgNPs has tested against selected pathogens and positive test results were attained. As a result, the synthesized AgNPs were exhibited effective antimicrobial activity for innovative biological applications in medical field. © 2016 Elsevier Ltd.