A method of recovering molybdenum from the catalyst residue derived from the process of epoxidizing olefins is disclosed. The catalyst residue, in semi-solid form or as a solution diluted in an organic solvent, is contacted with an aqueous solution of an oxidizing agent such as hydrogen peroxide, nitric acid, or sodium hypochlorite to transfer the molybdenum to the aqueous solution. The molybdenum is thereafter isolated directly from the aqueous solution or, alternatively, from the aqueous solution following preconcentration by liquid-liquid or liquid-solid extraction.