Ozone was a useful tool very early in the history of structural studies involving fatty acids and their derivatives. More recently the productions of azelaic and pelargonic acids by the ozonolysis of oleic acid has become of commercial importance. This paper reviews the chemistry of the ozonolysis of various unsaturated fatty acids and their derivatives. The products can be varied from a single starting material depending on the manner of decomposing the intermediate ozonide. Thus, variations in starting material and variations in procedure make possible a great variety of straight chain products containing one or two functional groups such as carboxyl, aldehyde, hydroxyl, and amino.