Nanoparticles are of great interest in the scientific community particularly in medical field because of their unique properties. Biological synthesis of silver nanoparticles has received a tremendous attention and has been a focus of research due to their high chemical, thermal stability and promising applications in medicinal field due to its environment friendly approach and also low cost techniques. However, the important challenging issues in current nanotechnology include the development of reliable experimental techniques for the synthesis of nanoparticles of different compositions and sizes along with high monodispersity. Use of microbes such as bacteria, fungi and yeasts in the synthesis of nanoparticles is a new and exciting area of research with considerable potential for development