In the present investigation, we report the extracellular biosynthesis of silver nanoparticles (AgNP) employing the fungus Cladosporium cladosporioides. The extracellular solution of C. cladosporioides was used for the reduction of AgNO(3) solution to AgNP. The present study includes time dependent formation of AgNP employing UV-vis spectrophotometer, size and morphology by employing TEM (transmission electron microscopy), structure from powder X-ray diffraction (XRD) technique and understanding of protein-AgNP interaction from Fourier transform infrared (FT-IR) spectroscopy. The AgNP were 10-100nm in dimensions as measured by TEM images.