The development of an advanced alloying process using Micro-Electrical Discharge Machining Deposition is described in the present paper. The new process uses a micro -sized bi-metal tool electrode, which is composed of two halves; each part made of a different metal. The alloying process of the two metals occurs during the deposition process previously proposed by the authors, which can create 3-dimensional micro-sized objects. The quality of alloyed metal was verified using X-ray analysis. In the present experiment the two metals used are YNi-1 (nickel alloy used in TIG welding) and S45C (medium carbon steel). EPMA results of the obtained deposit show that the nickel and iron distribution in the deposit is uniform when the tool electrode spins during the deposition process. Also, it was found that the chemical composition of the main metal in the deposited object is proportional to the cross sectional area in the bi-metal electrode section. Therefore, not only the deposition process takes place but also the chemical composition of the deposit can be simultaneously controlled using this process.