<b>Silver Nanoparticles from a Plant Echinacea Purpurea Extract for its Antipathogenic Efficacy</b> Nanotechnology is gaining tremendous impetus in the present century due to its capability of modulating metals into their nanosize. The synthesis, characterization, and application of biologically synthesized nanomaterials have become an important branch of nanotechnology. Research in nanotechnology highlights the possibility of green chemistry pathways to produce technologically important nanomaterials. Metallic nanoparticles are traditionally synthesized by wet chemical techniques, where the chemicals used are often toxic and flammable. Silver nanoparticles are the metal of choice as they hold the promise to kill microbes effectively. The present study describes a cost effective and environment friendly technique for green synthesis of silver nanoparticles from 1mM silver nitrate solution through the a plant Echinacea purpurea cone flower extract. The appearance of brown colour indicates the synthesis of silver nanoparticles. Nanoparticles were characterized using UV Vis absorption spectroscopy and SEM analysis. UV Vis spectrum of the aqueous medium containing silver nanoparticles showed absorption peak at 450nm. SEM analysis showed the average particle size of 50 70nm and spherical shape of the silver nanoparticles. Further studies on the silver nanoparticles showed that it has the antibacterial activities. Antipathogenic activity study was carried out by spread plate, pour plate on Escherichia coli and disc diffusion methods on pathogenic organisms such as Escherichia coli, Proteus vulgaricus, Klebsiella pneumoniae, Pseudomonas aeruginosa. Compared to spread plate, pour plate method showed the maximum antibacterial activity. Zone of inhibition was observed by disc diffusion methods and among these four pathogens, Klebsiella pneumoniae and Escherichia coli showed the maximum activity. Silver nanoparticles, Antipathogenic, Plant extract 18-20 Issue-6 Volume-6 Satheesh Kumar B.