Nanotechnology, with its main focus on production, characterization, manipulation and application of nano sized particles that has at least one dimension of less than 100 nm, is an emerging field in the area of biology. In this study we have done biosynthesis of silver nanoparticles (AgNPs) from Aspergillus niger. The strain was characterized by biochemical and molecular characterization. AgNPs were characterized by UV-VIS spectroscopy and SEM-EDS. The antimicrobial activity of AgNPs was also determined.