Polymer/metal nanocomposites have attracted great attention because of the combination of both the properties of the inorganic nanoparticles such as optical antimicrobial electrical or mechanical properties and those of the polymer such as processability solubility and chemical resistance1-4. However the dispersion of nanoparticles into a polymer matrix has been a bottleneck for nanocomposite fabrication. Silver nanoparticles have attracted particular interest due to their favorable optical properties displaying surface plasmon resonance non-linear optical limitation electrical properties ability to modify the refractive index of host materials catalysis conductive inks thick film pastes adhesives for various electronic components and superior to other metals in antibacterial effects1-5.In this study we have attempted to develop organic-inorganic hybrid polyurethane silver nanocomposite (Ag/LPOSiPU) coatings. Synthesis carried out in three steps- (i) synthesis of organic-inorganic hybrids (LPOSi) from linseed oil polyol (LPO) as organic and tetraethoxyorthosilane (TEOS) as inorganic precursors respectively through sol-gel process (ii) preparation of silver nano-particles in organic-inorganic hybrids (LPOSi) via reduction of silver salt (AgNO3) by employing NN_-dimethylformamide (DMF) as reducing agent at room temperature to obtain Ag/LPOSi and (iii) Ag/LPOSi further treated with toluene 24 di-isocyanate to form their polyurethane (Ag/LPOSiPU). Ag/LPOSiPU was applied on mild steel strips to evaluate their coating performance. The structure morphology and thermal stability of the resulting Ag/LPOSiPU have been investigated by FTIR X-ray diffraction transmission electron microscopy (TEM) scanning electron microscopy (SEM) UV-visible and thermogravimetric analysis (TGA). The physico-mechanical (scratch hardness impact resistance bend test) and corrosion/chemical resistance (by weight loss and electrochemical method in various corrosive media such as 3.5%HCl 3.5%NaOH Xylene Salt mist test) performance were conducted to evaluate the coating properties of synthesized Ag/LPOSiPU. The antimicrobial efficacy of Ag/LPOSiPU was also premeditated and highly antibacterial activity against Gram negative bacteria (Escherichia coli) and Gram positive bacteria (Staphylococcus aureus) were observed. The synthesized Ag/LPOSiPU materials exhibit fairly good thermal resistivity and can be safely employed up to 240 oC which serve as novel and promising candidates for use as nanostructured antimicrobial corrosion protective coating materials. Keywords: Biohybrid Nanocomposite silver nanoparticles Antimicrobial Coating References 1 Akram D.; Ahmad.; S.; Sharmin E.; Ahmad S Macromol.Chem.Phys.2010 211 4122 Jiang H. C.; Chen W. M.; Chen C. Y.; Xiong S. X.; Yu A.B Nanoscale. Res.Lett. 2010.3 Kumar A.; Vemula P. K.; Ajayan P.M.; John G Nature Materials 2008 7 236.4 Konwar U.; Karak N.; Mandal. M Prog. Org. Coat. 2010 68 265.