This article reviews the solubilities of the common gases present in ferrous metals, such as cast irons, and nonferrous metals, such as aluminum, copper, magnesium, and their alloys. The kinetics of the relevant reactions, reactions during solidification, and possible methods of control or removal of the dissolved gases are discussed. The most common method for removing hydrogen from aluminum, copper, and magnesium is inert gas flushing. The article provides information on techniques to overcome gas porosity in ferrous and nonferrous metals.