Joining of dissimilar metals is to compose different properties of metals in order to minimize material costs and at the same time to maximize the performance of the equipment and machinery. There are a lot of methods of joining of dissimilar metals. However, the fusion welding is mostly used in a wide range of industries. This research is carried out for the process of dissimilar welding between carbon steel plates of ASTM A516-70 and austenitic stainless steel plates ASTM A214-316L by using gas metal arc welding (GMAW). Welding design used is a V-groove by using the buttering process and without buttering (non-buttering) process. Types of filler metals used are ER309L and ER316L-Si. The weldment is then tested by using destructive test (DT) and nondestructive test (NDT). Weldment is also characterized by using X-Ray Diffraction (XRD). The results show that the mechanical properties of weldment with buttering process are better compared with the weldment with a non-buttering process. The macro and microstructure of weldment with buttering process revealed finer grained and homogeneous structures compared with the one by using a non-buttering process. Moreover, welds characterization by using XRD show that the precipitation of chromium carbide on HAZ of weldment with buttering process is lower than that of weldment with a non-buttering process.