In accordance with the present invention, .-hydroxy-20-ketosteroids are prepared by the oxidation of 20-ketosteriods, such as 3-methoxy-pregna-3,5-dien-20-one. The 3-methoxypregna-3,5-dien-20-one is prepared from progesterone by methods well known in the art. The pregn-20-ones, such as 3-methoxypregna-3,5-dien-20-one, are oxidized with oxygen or air using a base catalyst in the presence of a phosphite reducing agent in a suitable solvent. The base catalyst consists of an alkali metal tert-alkoxide, which can be prepared from an alkali metal and a tert-alkanol. The oxidation reaction can be carried out at any temperature from about -. C. to about . C. and for a period of 2-20 hours depending on the temperature at which the reaction is carried out. For example, at ambient temperature the rate of oxidation is sufficiently fast to complete the oxidation in 2 to 4 hours. This method for preparing .-hydroxy-20-ketosteroids from 20-ketosteroids is an important and valuable step in preparing corticosteroids and other hormones.