Fluoroxy-halo-compounds are prepared 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 a gaseous phase, at an absolute pressure of between 50 and 800 kPa and at a temperature higher than -50°C and up to 250°C, under conditions of continuous feeding of the reactants and a continuous removal of the reaction product.