α-Diketones are widely used in various branches of industry as photoinitiators in radical polymerization, paint curing, preparation of highly sensitive photoresists, polymer grafting, dental resins, as macrophotoinitiators, etc. In this review, various methods of α-diketone preparation are presented and classified according to the starting material structure. Oxidation of ketones having in the α-position the methylene group, the hydroxy group, a halogen atom or other functional groups is described. Methods of preparation of unsaturated ?-dicarbonyl compounds are described as well.