[en] In order to study the potential release of radioactivity from Spanish phosphogypsum to the aquatic medium, we have designed laboratory forced leaching experiments to evaluate the degree of transference with time of ²²⁶Ra and uranium isotopes from phosphogypsum to water. In these experiments, aliquots containing a 1:3 proportion of phosphogypsum in water were stirred under laboratory conditions during several time intervals. After stirring, leachates were filtered and their ²²⁶Ra and ^234,238U concentrations were determined by alpha-particle spectrometry. Several and important conclusions can be remarked from the obtained results of this experimental work: i) the radium transfer from phosphogypsum to water is less than in the case of uranium, ii) the transference of radium is clearly reduced when leaching experiments are performed with fresh water instead of marine water, iii) the final ²²⁶Ra concentration in leachates is indirectly related with the solubility of phosphogypsum in water, and, iv) the concentration of uranium isotopes in the leachates seems to be strongly related with the presence of traces of non-separated phosphoric acid in the phosphogypsum matrix. (author)