 In this study, biological synthesis of silver nanoparticles, AGNPs, from supernatant of endophytic fungus-alternaria SP isolated from the healthy leaves of refina sativus was investigated. Characterization of the synth-sized AGNPs included UV vis spectroscopy, FTIR, powder x-ray diffraction, XRD, dynamic light scattering, DLs, transmission electron microscopy, TEM, and atomic force microscopy, AFM. The AGNPs were found to be spherical in shape with an average particle size of 4 to 30 nanometers and highly toxic against human pathogenic bacteria. This suggests the potential use of AGNPs as effective antibacterial agents. This article was authored by Tej Singh, Kumari Jutee, Amar Patnaik, and others.