A facile bottom-up ‘green’ and rapid synthetic route using Murraya Koenigii leaf extract as reducing and stabilizing agent produced silver nanoparticles at ambient conditions and gold nanoparticles at 373K. The nanoparticles were characterized using UV–vis, transmission electron microscopy (TEM), X-ray diffraction (XRD) and FTIR analysis. This method allows the synthesis of well-dispersed silver and gold nanoparticles having size ∼10nm and ∼20nm, respectively. Silver nanoparticles with size ∼10nm having symmetric SPR band centered at 411nm is obtained within 5min of addition of the extract to the solution of AgNO 3 at room temperature. Nearly spherical gold nanoparticles having size ∼20nm with SPR at 532nm is obtained on adding the leaf extract to the boiling solution of HAuCl 4 . Crystallinity of the nanoparticles is confirmed from the high-resolution TEM images, selected area electron diffraction (SAED) and XRD patterns. From the FTIR spectra it is found that the biomolecules responsible for capping are different in gold and silver nanoparticles. A comparison of the present work with the author's earlier reports on biosynthesis is also included.