Microwave irradiation is a novel method to accelerate the preparation of inorganic nanoparticles as well as various nanostructures such as nanotubes, nanorods, and nanowires. In this research, silver (Ag) nanostructures with various morphologies were prepared via a rapid microwave-assisted technique. The spherical and polygonal Ag nanoparticles were synthesized in the presence of Polyvinilpyroliden (PVP) as stabilizing agent. Ethylene glycol (EG) serves as a solvent. The silver nanoparticles were produced by Continuous and Discontinuous Wave irradiation. The obtained materials were characterized by UV-visible and transmission electron microscopy (TEM). The results present that the size of nanoparticles increase in continuous irradiation. In this process, the morphology of product is polygonal. In the discontinuous process the colloidal particle size is smaller than that obtained from the continuous process. Furthermore, the Ag nanoparticles have spherical shapes. The final data show that microwave processing has unique advantages over conventional heating processes.