Process for the preparation of perfluorocarboxylic acids of the formula RF—COOH, salts thereof and esters thereof from perfluoroalkyl iodides of the formula RF′—I, in which RF and RF′ are cyclic, branched or linear, saturated or unsaturated perfluoroalkyl radicals, by activating the perfluoroalkyl iodides in the presence of oxygen and in organic solvents.