Preparation of fluoroxy-halo-compounds by direct reaction between fluorine and organic compounds having a molecular structure in which at least one oxygen atom is directly bound to a carbon atom in the carbonylic form, in the presence of a fluorination catalyst, in gaseous phase, at an absolute pressure of between 50 and 800 kPa and at a temperature between -5.degree. and +100.degree. C., under conditions of a continuous feeding of the reactants and a continuous removal of the reaction product.