To our knowledge, the MW heating is created by the interaction of the dipole moment of molecules with the high-frequency electromagnetic radiation. Water has a very high dipole moment, which makes it one of the best solvents for MW heating. In the past, gold and silver nanomaterials have been prepared by using citrate aqueous solution as reduction and stabilization reagent [18] and [19]. Mild reaction temperature (ca. 100 °C) is sufficient for the synthesis of these materials. However, no work has been reported on the use of spherical-shaped gold seed to assist the growth of silver nanomaterials, especially in the formation of anisotropic-shaped in mild reaction under MW heating process. In the present work, the preparation of silver nanomaterials using MW heating is described. We investigate a novel method of the combination of clean (without the present of polymers, surfactants, and templates) and mild (with reaction temperature ca. 100 °C) solution-phase approach that allows producing silver nanorods. In this technique, gold nanoparticles as the core metal are produced initially, and then the silver ions of the shell metal are reduced onto the surface of the core particles. How does the gold seed volume affect the result of the experiment? The experiment reports here provide insight into the question.