The present invention relates to a catalyst containing a vanadium-phosphorus oxide and an alkali metal, wherein the proportion by weight of alkali metal in the vanadium-phosphorus oxide is in the range from 10 to 400 ppm, based on the total weight of the vanadium-phosphorus oxide, a process for producing it and also the use of the catalyst for the gas-phase oxidation of hydrocarbons, in particular for preparing maleic anhydride.