The present study, we deals a cost effective and environment friendly technique for green synthesis silver nanoparticles from 1 mM AgNo3 solution through the extract of L. aspera leaves as reducing and capping agent. The silver nanaoparticles formation was confirmed by the colour change of plant extracts and further confirmed with the help of UV-Vis spectrum. These photosynthesized silver nanoparticles were tested for antimicrobial activity using agar well-diffusion method. The microbial cultures are Staphylococcus aureus, Bacillus cereus, Escherichia coli, Klebsiella pneumoniae, Salmonella typhi and Proteus vulgaris of bacteria and Aspergillus niger, Candida albicans of fungal were used. The biologically synthesized nanoparticles exhibited a tremendous antimicrobial activity. Gram negative bacteria showed maximum antimicrobial activity against synthesized silver nanoparticles in comparison with gram positive bacteria.