10.22376/ijpbs.2019.10.1.p1-12 Volume 8 Issue 1 2017 (January - March) Synthesis of silver nanoparticles (Ag -NPs) using sustainable thermo-chemical method have drawn considerable interest in the field of nanotechnology. Polysaccharides have been used as stabilizing and reducing agents for the synthesis of silver nanoparticles. In the present investigation two different sources of starch (synthetic starch, rice starch) have been used to reduce precursor of Ag ions for the rate of nucleation and size distribution of silver nanoparticles. The synthesized silver nanoparticles were adopted to characterize by UV-visible spectroscopy, field emission scanning electron microscope (FESEM) analysis and antibacterial assay. The surface plasmon resonance (SPR) absorption of nanoparticles was monitored by using UV-visible spectrophotometer and maximum peaked at 440nm and 420nm respectively. The FESEM micrograph of synthetic starch mediated silver nanoparticles shows that an irregular shaped with size range of 60-100nm and natural starch mediated silver nanoparticles demonstrate that spherical shaped nanoparticles having the size range of 60-80nm. Natural starch mediated silver nanoparticles showed highest antibacterial activity (25 mm) against lessThan i greaterThan Shigella lessThan /i greaterThan sp. Among the bacterial pathogens tested Gram negative bactria are more susceptible than the Gram positive bacteria by the nanoparticle synthesized using natural starch as a reducing and stabilizing agent. Thermo-chemical mediated natural starch induced silver nanomaterials can be considered as reliable, eco-friendly and cost effective approach and evident by the properties of the nanoparticles. S. KRISHNAKUMAR, G. RAMANATHAN AND R. J. HEMALATHA silver nanoparticles, polysaccharide, starch, FESEM analysis, antibacterial 1-7