It is the purpose of this paper to review the more common residual elements in austenitic stainless steels. Their effects on work hardening, surface, corrosion resistance, welding, etc., will be noted where information is available. An arbitrary limit of 0.05 per cent per residual element will be used as a guide. Experiments and experience at Allegheny Ludlum Steel Corp. with residuals exceeding 0.05 per cent will also be reviewed. It is intended to point out the harmful effects of certain elements and emphasize the satisfactory results obtained with other residuals in standard grades. Residual elements can be grouped into several categories—austenitizers, ferritizers, carbide formers, interstitials, etc. Copper, nitrogen, and cobalt are called austenitizers principally because they promote the formation and stability of austenite. Nickel, manganese, and carbon are other austenite-stabilizing elements and are an integral part of standard analyses. Aluminum, molybdenum, and silicon fall into the category of ferritizers, in that they promote the formation of ferrite. Other elements such as tungsten, vanadium, columbium, etc., can combine with the carbon to form carbides with remaining percentages acting as ferrite formers and going into solid solution. Hydrogen and oxygen are classified as interstitials.