Plasma-metal inert gas (MIG) welding can be defined as a combination of plasma arc welding (PAW) and gas-metal arc welding (GMAW) within a single torch, where a filler wire is fed through the plasma nozzle orifice. This article describes the principles of operation and operating modes of plasma-MIG welding. It discusses the advantages and disadvantages of the plasma-MIG process. The article describes the components, including power sources and welding torches, of equipment used for the plasma-MIG process. It provides information on inspection and weld quality control and troubleshooting techniques. The article concludes with a discussion on the applications of the plasma-MIG process.