Few places in the world produce iodine-125. In Brazil, the first production was achieved by using the IEA-R1 nuclear reactor located at Nuclear and Energy Research Institute ??? IPEN. To verify the quality of iodine-125 produced, and the amount of contaminants such as iodine-126, cesium-134 and caesium-137 among others, iodine-125 samples were immobilized into epoxy matrix disc, with the same geometry of a barium-133 reference radioactive source, used to calibrate an HPGe detector. The HPGe detector has a thin carbon composite window, which allows measure the iodine-125 photopeaks, between 27.1 and 35.4 keV. The method employed here was successful in producing and measurement of iodine-125.Funda????o de Amparo ?? Pesquisa do Estado de S??o Paulo (FAPESP)FAPESP: 01/04768-3