Diethylstilbestrol (DES) is a synthetic non-steroidal estrogen, pharmacologic effects of which resemble natural estrons; today it is being used to treat some types of postmenopausal breast cancer and advanced prostate cancer. The aim of current study is conjugation of glucuronic acid (G) to DES and to evaluate radiopharmaceutical potential of this estrogen glucuronide derivative (DESG) which is specific to beta glucuronidase enzyme consisting tumor cells. Taking into consideration the compatibility to the chemical structures of the synthesized product, I-131 and I-125 were chosen as the appropriate radionuclides and DESG was labeled with these radionuclides utilizing iodogen method. The radiochemical yields of I-125/131-DESG were over 90 % according to thin layer radio chromatography method. The biodistribution of I-131-DESG in healthy female Wistar Albino rats has been investigated and the range of the breast/blood and breast/muscle ratios were approximately 2 and 13 in 240 min for ER unsaturated studies. Effects of the radioiodinated DES and DESG on the cells were examined using MCF-7, A-549, Caco-2 cell lines. I-125-DESG has higher incorporation percentages than I-125-DES on MCF-7 cells. The radioiodinated DESG has the desired radiopharmaceutical properties which could be candidate radiopharmaceuticals for diagnosis and especially radionuclide therapy of breast tumors.