10.22376/ijpbs.2019.10.1.p1-12 Volume 4 Issue 3 2013 (July - September) The synthesis of nanomaterials is a cornerstone of nanotechnology. Most of the synthesis methods encompassing chemical routes have led to environmental pollution, especially the bi-products associated with metal production. Here we report an environmentally benign and cost effective approach in synthesizing silver nanoparticles using leaf extracts of lessThan i greaterThan Alternanthera ficoidea lessThan /i greaterThan . The surface plasmon resonance of silver nanoparticles produced a peak centered near 410nm was characterized by UV-Visible spectrophotometer. Silver nanoparticles were circular in shape with maximum particles in size range within 4–22 nm as observed under Transmission electron microscope (TEM). As-synthesized silver nanoparticles were also found to inhibit the growth of two gram negative clinical bacterial isolates lessThan i greaterThan Escherichia coli lessThan /i greaterThan , and lessThan i greaterThan Serratia marcescens lessThan /i greaterThan . MRINAL KUMAR BAISHYA,DEBABRAT BAISHYA AND MOHAN CHANDRA KALITA Alternanthera ficoidea, silver nanoparticles, transmission electron microscope, antibacterial potential 104-110