In this study, we report the synthesis of silver nanoparticles from cinnamon bark extract. The physical charactrization of these silver nanoparticles was verified using UV-visible spectroscopy, scanning electron microscopy, and powder X-ray diffraction. Size distribution of nanoparticles was in the range of 30 to 150 nm. The zeta potential was -32 mV, indicating dispersion ability. Superoxide anion radical scavenging assay showed 82% activity for silver nanoparticles derived from cinnamon bark extract. © 2015 Bentham Science Publishers.