Stainless steel is the most versatile and widely used material in the industries.It is used in each and every aspects of life like infrastructure development, defense,heavy machinery industries, automobile etc.Industries use conventional welding processes to weld stainless steel. The basic problems that are associated with those conventional welding processes like GMAW, GTAW and arc welding of stainless steel are hydrogen embrittlement, distortion and non ecofriendly nature.Friction stir welding(FSW) being a solid state welding process is free from most of defects usually produced in fusion welding processes (because of considerably lower heat input and absence of melting) . Apart from this, it has many advantages like improved mechanical properties of weldment, graining refining, and improves corrosion resistance, improved productivity and no requirement of filler material. In this book,feasibilty of welding of Stainless Steel 304 using FSW has been attempted using innovative fixture design. FSW operation is performed on retrofitted vertical milling machine. Classification of Stainless steels, their properties and applications has also explained in depth.