An industrially suitable process for producing a higher carbonyl compound by the oxidation of an olefinic compound having at least six carbon atoms is provided. Said improved process comprises oxidizing the olefinic compound in aqueous medium containing palladium or salt thereof and a copper salt in the presence of a specific water-soluble polyoxyalkylene compound in an amount of from about 1/4 to about 3 parts by weight per 1 part by weight of water contained in the reaction mixture. The improvement is demonstrated in terms of yield, selectivity, separation of the product, and recycle of the catalyst.