text: Many methods exist for the preparation of ketones in industrial scale and academic laboratories. Ketones are also produced in various ways by organisms; see the section on biochemistry below.
  In industry, the most important method probably involves oxidation of hydrocarbons, often with air. For example, a billion kilograms of cyclohexanone are produced annually by aerobic oxidation of cyclohexane. Acetone is prepared by air-oxidation of cumene.
  For specialized or small scale organic synthetic applications, ketones are often prepared by oxidation of secondary alcohols:
  Typical strong oxidants (source of "O" in the above reaction) include potassium permanganate or a Cr(VI) compound. Milder conditions make use of the Dess–Martin periodinane or the Moffatt–Swern methods.
  Many other methods have been developed, examples include:
  * By geminal halide hydrolysis.
  * By hydration of alkynes. Such processes occur via enols and require the presence of an acid and mercury(II) sulfate (). Subsequent enol–keto tautomerization gives a ketone. This reaction always produces a ketone, even with a terminal alkyne, the only exception being the hydration of acetylene, which produces acetaldehyde.
  *From Weinreb Amides using stoichiometric organometallic reagents.
  * Aromatic ketones can be prepared in the Friedel–Crafts acylation, the related Houben–Hoesch reaction, and the Fries rearrangement.
  * Ozonolysis, and related dihydroxylation/oxidative sequences, cleave alkenes to give aldehydes or ketones, depending on alkene substitution pattern.
  * In the Kornblum–DeLaMare rearrangement ketones are prepared from peroxides and base.
  * In the Ruzicka cyclization, cyclic ketones are prepared from dicarboxylic acids.
  * In the Nef reaction, ketones form by hydrolysis of salts of secondary nitro compounds.
  * In the Fukuyama coupling, ketones form from a thioester and an organozinc compound.
  * By the reaction of an acid chloride with organocadmium compounds or organocopper compounds.
  * The Dakin–West reaction provides an efficient method for preparation of certain methyl ketones from carboxylic acids.
  * Ketones can be prepared by the reaction of Grignard reagents with nitriles, followed by hydrolysis.
  * By decarboxylation of carboxylic anhydride.
  * Ketones can be prepared from haloketones in reductive dehalogenation of halo ketones.
  * In ketonic decarboxylation symmetrical ketones are prepared from carboxylic acids.
  * Hydrolysis of unsaturated secondary amides, β-Keto acid esters, or β-diketones (the acetoacetic ester synthesis).  
  * Acid-catalysed rearrangement of 1,2-diols, or Criegee oxidation of the same.