Abstract: In the process for obtaining phenol and acetone from cumene hydroperoxide which has been obtained by liquid-phase oxidation of cumene with molecular oxygen, dehydration of by-product dimethyl phenyl carbinol to form alpha-methylstyrene and formation of higher boiling by-products, such as alpha-methylstyrene dimers and cumyl phenol, are substantially reduced by an improvement which comprises, in combination: decomposing the cumene hydroperoxide at temperatures in the range of from 65.degree. to 105.degree. C. using as decomposition catalyst sulfur dioxide or sulfuric acid in amount of between 0.002 and 0.02 percent by weight of the cumene hydroperoxide feed, conducting the decomposition in the absence of added water in a decomposition mixture containing not more than about 0.5 percent by weight of water, and withdrawing decomposition product at cumene hydroperoxide concentrations not exceeding about 0.